Method and apparatus for performing channel coding and decoding in communication or broadcasting system

ABSTRACT

Disclosed is a method performed by a user equipment (UE) in a communication system, including receiving, from a base station, downlink control information including resource assignment information of a physical downlink shared channel (PDSCH), identifying a number of resource elements (REs) for the PDSCH based on the resource assignment information of the PDSCH, identifying a temporary transport block size (TBS) based on the number of REs for the PDSCH, identifying a TBS based on the temporary TBS, and receiving, from the base station, the PDSCH based on the TBS, wherein the number of REs for the PDSCH is identified by excluding a number of REs associated with a channel state information reference signal (CSI-RS) and a control channel.

PRIORITY

This application is a Continuation application of U.S. patentapplication Ser. No. 16/621,156, which was filed on Dec. 10, 2019, whichis a National Phase Entry of PCT International Application No.PCT/KR2018/006761 which was filed on Jun. 15, 2018, and claims priorityto Korean Patent Application Nos. 10-2017-0075935 and 10-2017-0082027,which were filed on Jun. 15, 2017 and Jun. 28, 2017, respectively, thecontents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates to a method and an apparatus for performingchannel coding and decoding in a communication or broadcasting system.

BACKGROUND ART

In order to meet wireless data traffic demands that have increased after4G communication system commercialization, efforts to develop animproved 5G communication system or a pre-5G communication system havebeen made. For this reason, the 5G communication system or the pre-5Gcommunication system is called a beyond 4G network communication systemor a post LTE system. In order to achieve a high data transmission rate,an implementation of the 5G communication system in a mmWave band (forexample, 60 GHz band) is being considered. In the 5G communicationsystem, technologies such as beamforming, massive MIMO, full dimensionalMIMO (FD-MIMO), array antenna, analog beam-forming, and large scaleantenna are being discussed as means to mitigate a propagation path lossin the mmWave band and increase a propagation transmission distance.Further, the 5G communication system has developed technologies such asan evolved small cell, an advanced small cell, a cloud radio accessnetwork (RAN), an ultra-dense network, device to device communication(D2D), a wireless backhaul, a moving network, cooperative communication,coordinated multi-points (CoMP), and received interference cancellationto improve the system network. In addition, the 5G system has developedadvanced coding modulation (ACM) schemes such as hybrid FSK and QAMmodulation (FQAM) and sliding window superposition coding (SWSC), andadvanced access technologies such as filter bank multi carrier (FBMC),non orthogonal multiple access (NOMA), and sparse code multiple access(SCMA).

Meanwhile, the Internet has been evolved to an Internet of Things (IoT)network in which distributed components such as objects exchange andprocess information from a human-oriented connection network in whichhumans generate and consume information. An Internet of everything (IoE)technology in which a big data processing technology through aconnection with a cloud server or the like is combined with the IoTtechnology has emerged. In order to implement IoT, technical factorssuch as a sensing technique, wired/wireless communication, networkinfrastructure, service-interface technology, and security technologyare required, and research on technologies such as a sensor network,machine-to-machine (M2M) communication, machine-type communication(MTC), and the like for connection between objects has recently beenconducted. In an IoT environment, through collection and analysis ofdata generated in connected objects, an intelligent Internet technology(IT) service to create a new value for peoples' lives may be provided.The IoT may be applied to fields, such as a smart home, smart building,smart city, smart car, connected car, smart grid, health care, smarthome appliance, or high-tech medical service, through the convergence ofthe conventional Information technology (IT) and various industries.

Accordingly, various attempts to apply the 5G communication system tothe IoT network are made. For example, technologies such as a sensornetwork, machine-to-machine (M2M), and machine-type communication (MTC)are implemented by beamforming, MIMO, and array antenna schemes. Theapplication of a cloud RAN as the big data processing technology may bean example of convergence of the 5G technology and the IoT technology.

In a communication/broadcasting system, link performance maysignificantly deteriorate due to various channel noise, fadingphenomenon, and inter-symbol interference (ISI). Accordingly, in orderto realize high-speed digital communication and broadcasting systemsthat require high data throughput and high reliability such asnext-generation mobile communication, digital broadcasting, and portableInternet, it is needed to develop a technology for removing noise,fading, and inter-symbol interference. As research on noise removal,research on an error correcting code is actively performed recently fora method of increasing reliability of communication by efficientlyreconstructing distortion of information.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

The disclosure provides a method and an apparatus for transmitting acoding bit which may support various input lengths and code rates.Further, the disclosure provides a method of configuring a base graph ofan LDPC code used for data channel transmission and a method and anapparatus for segmenting a transport block using the LDPC code.

Solution to Problem

In accordance with an aspect of the disclosure, a method performed by auser equipment (UE) in a communication system includes receiving, from abase station, downlink control information including resource assignmentinformation of a physical downlink shared channel (PDSCH), identifying anumber of resource elements (REs) for the PDSCH based on the resourceassignment information of the PDSCH, identifying a temporary transportblock size (TBS) based on the number of REs for the PDSCH, identifying aTBS based on the temporary TBS, and receiving, from the base station,the PDSCH based on the TBS, wherein the number of REs for the PDSCH isidentified by excluding a number of REs associated with a channel stateinformation reference signal (CSI-RS) and a control channel.

In accordance with an aspect of the disclosure, a method performed by abase station in a communication system includes transmitting, to a UE,downlink control information including resource assignment informationof a PDSCH, identifying a number of REs for the PDSCH according to theresource assignment information of the PDSCH, identifying a temporaryTBS based on the number of REs for the PDSCH, identifying a TBS based onthe temporary TBS, and transmitting, to the UE, the PDSCH based on theTBS, wherein the number of REs for the PDSCH is identified by excludinga number of REs associated with a CSI-RS and a control channel.

In accordance with an aspect of the disclosure, a UE in a communicationsystem includes a transceiver, and a controller configured to receive,from a base station, downlink control information including resourceassignment information of a PDSCH, identify a number of REs for thePDSCH based on the resource assignment information of the PDSCH,identify a temporary TBS, based on the number of REs for the PDSCH,identify a TBS based on the temporary TBS, and receive, from the basestation, the PDSCH based on the TBS, wherein the number of REs for thePDSCH is identified by excluding a number of REs associated with aCSI-RS and a control channel.

In accordance with an aspect of the disclosure, a base station in acommunication system includes a transceiver; and a controller configuredto transmit, to a UE, downlink control information including resourceassignment information of a PDSCH, identify a number of REs for thePDSCH according to the resource assignment information of the PDSCH,identify a temporary TBS based on the number of REs for the PDSCH,identify a TBS based on the temporary TBS, and transmit, to the UE, thePDSCH based on the TBS, wherein the number of REs for the PDSCH isidentified by excluding a number of REs associated with a CSI-RS and acontrol channel.

Advantageous Effects of Invention

The disclosure can satisfy various service requirements of anext-generation mobile communication system using an LDPC code that canbe applied to a variable length and a variable rate. Further, thedisclosure can support efficient operation of the LDPC which is a datachannel coding method.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates the structure of transmission in downlinktime-frequency domains in an LTE or LTE-A system;

FIG. 2 illustrates the uplink time-frequency domain transmissionstructure of the LTE or LTE-A system;

FIG. 3 illustrates the basic structure of a base graph of an LDPC code;

FIG. 4 is a block diagram illustrating an example of a receptionoperation of a terminal according to embodiment 1;

FIG. 5 is a block diagram illustrating an example of another receptionoperation of the terminal according to embodiment 1;

FIG. 6 illustrates an example of segmenting a transport block into codeblocks according to embodiment 2;

FIG. 7 illustrates a method of segmenting a transport block according toembodiment 2;

FIG. 8 illustrates an example of segmenting a transport block into codeblocks according to embodiment 3;

FIG. 9 illustrates a method of segmenting a transport block according toembodiment 3;

FIG. 10 is a flowchart illustrating an example of an operation in whichthe eNB obtains a TBS according to embodiment 4;

FIG. 11 is a flowchart illustrating an example of an operation in whichthe terminal obtains a TBS according to embodiment 4;

FIG. 12 is a block diagram illustrating the structure of the terminalaccording to embodiments; and

FIG. 13 is a block diagram illustrating the structure of the eNBaccording to embodiments.

MODE FOR THE INVENTION

Hereinafter, embodiments of the disclosure will be described in detailwith reference to the accompanying drawings.

In describing the exemplary embodiments of the disclosure, descriptionsrelated to technical contents which are well-known in the art to whichthe disclosure pertains, and are not directly associated with thedisclosure, will be omitted. Such an omission of unnecessarydescriptions is intended to prevent obscuring of the main idea of thedisclosure and more clearly transfer the main idea.

For the same reason, in the accompanying drawings, some elements may beexaggerated, omitted, or schematically illustrated. Further, the size ofeach element does not entirely reflect the actual size. In the drawings,identical or corresponding elements are provided with identicalreference numerals.

The advantages and features of the disclosure and ways to achieve themwill be apparent by making reference to embodiments as described belowin detail in conjunction with the accompanying drawings. However, thedisclosure is not limited to the embodiments set forth below, but may beimplemented in various different forms. The following embodiments areprovided only to completely disclose the disclosure and inform thoseskilled in the art of the scope of the disclosure, and the disclosure isdefined only by the scope of the appended claims. Throughout thespecification, the same or like reference numerals designate the same orlike elements.

Here, it will be understood that each block of the flowchartillustrations, and combinations of blocks in the flowchartillustrations, can be implemented by computer program instructions.These computer program instructions can be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions specified in the flowchart block or blocks.These computer program instructions may also be stored in a computerusable or computer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer usable orcomputer-readable memory produce an article of manufacture includinginstruction means that implement the function specified in the flowchartblock or blocks. The computer program instructions may also be loadedonto a computer or other programmable data processing apparatus to causea series of operational steps to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions that execute on the computer or other programmableapparatus provide steps for implementing the functions specified in theflowchart block or blocks.

And each block of the flowchart illustrations may represent a module,segment, or portion of code, which includes one or more executableinstructions for implementing the specified logical function(s). Itshould also be noted that in some alternative implementations, thefunctions noted in the blocks may occur out of the order. For example,two blocks shown in succession may in fact be executed substantiallyconcurrently or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved.

As used herein, the “unit” refers to a software element or a hardwareelement, such as a Field Programmable Gate Array (FPGA) or anApplication Specific Integrated Circuit (ASIC), which performs apredetermined function. However, the “unit does not always have ameaning limited to software or hardware. The “unit” may be constructedeither to be stored in an addressable storage medium or to execute oneor more processors. Therefore, the “unit” includes, for example,software elements, object-oriented software elements, class elements ortask elements, processes, functions, properties, procedures,sub-routines, segments of a program code, drivers, firmware,micro-codes, circuits, data, database, data structures, tables, arrays,and parameters. The elements and functions provided by the “unit” may beeither combined into a smaller number of elements, “unit” or dividedinto a larger number of elements, “unit”. Moreover, the elements and“units” may be implemented to reproduce one or more CPUs within a deviceor a security multimedia card. Also, in an embodiment, ‘— unit’ mayinclude one or more processors.

A wireless communication system has developed to be a broadband wirelesscommunication system that provides a high speed and high quality packetdata service, like the communication standards, for example, high speedpacket access (HSPA) of 3GPP, long term evolution (LTE) or evolveduniversal terrestrial radio access (E-UTRA), LTE-advanced (LTE-A), highrate packet data (HRPD) of 3GPP2, ultra mobile broadband (UMB), and802.16e of IEEE, or the like, beyond the voice-based service provided atthe initial stage. Also, a communication standard of 5G or new radio(NR) is being developed as a 5^(th)-generation wireless communicationsystem.

As described above, the wireless communication system including 5thgeneration may provide at least one service of enhanced mobile broadband(eMBB), massive machine type communications (mMTC), and ultra-reliableand low-latency communications (URLLC) to a terminal. The services maybe provided to the same terminal during the same time interval. The eMBBmay be a service aiming at high-speed transmission of high-capacitydata, the mMTC may be a service aiming at minimization of terminal powerconsumption and access of a plurality of terminals, and the URLLC may bea service aiming at high reliability and low latency, but are notlimited thereto. The three services may be main scenarios in an LTEsystem or a system such as 5G or new radio (or next radio (NR)) afterLTE.

Hereinafter, an embodiment of the disclosure will be described in detailwith reference to the accompanying drawings. In the followingdescription of the disclosure, a detailed description of known functionsor configurations incorporated herein will be omitted when it may makethe subject matter of the disclosure rather unclear. The terms whichwill be described below are terms defined in consideration of thefunctions in the disclosure, and may be different according to users,intentions of the users, or customs. Therefore, the definitions of theterms should be made based on the contents throughout the specification.

Hereinafter, the eNB is the entity that allocates resources to theterminal and may be at least one of a gNode B, an eNode B, a Node B, abase station (BS), a radio access unit, an eNB controller, and a node ona network. The terminal may include a user equipment (UE), a mobilestation (MS), a cellular phone, a smart phone, a computer, or amultimedia system capable of performing a communication function. In thedisclosure, a downlink (DL) refers to a wireless transmission path of asignal that the eNB transmits to the terminal, and an uplink (UL) refersto a wireless transmission path of a signal that the terminal transmitsto the eNB.

Embodiments of the disclosure will be described on the basis of an LTEor LTE-A system or an NR system but may be applied to othercommunication systems having a similar technical background or channelform. Further, embodiments of the disclosure may be applied to othercommunication systems through some modifications without departing fromthe scope of the disclosure on the basis of determination by thoseskilled in the art.

An LTE system, which is a representative example of the broadbandwireless communication system, employs an orthogonal frequency divisionmultiplexing (OFDM) scheme for a downlink (DL) and employs a singlecarrier frequency division multiple access (SC-FDMA) scheme for anuplink (UL). In such a multi-access scheme, time-frequency resources forcarrying data or control information are allocated and operated in amanner to prevent overlapping of resources, that is, to establishorthogonality, between users so as to identify data or controlinformation of each user.

If decoding fails at the initial transmission, the LTE system employshybrid automatic repeat request (HARQ) that retransmits thecorresponding data in a physical layer. In the HARQ scheme, if areceiver does not accurately decode data, the receiver transmitsinformation (negative acknowledgement: NACK) informing a transmitter ofa decoding failure and thus the transmitter may re-transmit thecorresponding data on the physical layer. The receiver increases datareception performance by combining the data retransmitted by thetransmitter with the data of which decoding has previously failed. Ifthe receiver accurately decodes data, the receiver transmits information(ACK) reporting that decoding is successfully executed to thetransmitter so that the transmitter transmits new data.

Hereinafter, a higher layer signal according to the disclosure is asignal such as a system information block (SIB), radio resource control(RRC), or a media access control (MAC) control element (CE) andsemi-statically or/and statically supports specific operation control ofthe terminal, and a physical signal is an L1 signal and dynamicallysupports specific operation control of the terminal in the form ofUE-common downlink control information or UE-specific downlink controlinformation.

FIG. 1 illustrates a basic structure of time-frequency domains which areradio resource domains in which data or a control channel is transmittedin downlink of an LTE system or a system similar thereto.

Referring to FIG. 1 , the horizontal axis indicates the time domain andthe vertical axis indicates the frequency domain. A minimum transmissionunit in the time domain is an OFDM symbol. One slot 106 consists ofN_(symb) OFDM symbols 102 and one subframe 105 consists of 2 slots. Thelength of one slot is 0.5 ms, and the length of one subframe is 1.0 ms.A radio frame 114 is a time domain interval consisting of 10 subframes.In the frequency domain, the minimum transmission unit is a subcarrier.A bandwidth of the entire system transmission band consists of a totalof N_(B)W subcarriers 104. However, such detailed values may bevariable.

A basic unit of resources in the time-frequency domains is a resourceelement (RE) 112, and may be indicated by an OFDM symbol index and asubcarrier index. A Resource Block (RB or Physical Resource Block (PRB))108 is defined by N_(symb) successive OFDM symbols 102 in the timedomain and N_(RB) successive subcarriers 110 in the frequency domain.Accordingly, in one slot, one RB 108 may include N_(symb)×N_(RB) REs112. In general, a minimum data allocation unit in the frequency domainis the RB, and N_(symb)=7, N_(RB)=12, and N_(BW) may be proportional tothe bandwidth of the system transmission band in the LTE system. A datarate increases in proportion to the number of RBs scheduled for theterminal.

The LTE system may operate with definition of 6 transmission bandwidths.In the case of a frequency division duplex (FDD) system, in which thedownlink and the uplink are divided by the frequency, a downlinktransmission bandwidth and an uplink transmission bandwidth may bedifferent from each other. A channel bandwidth may indicate an RFbandwidth corresponding to a system transmission bandwidth. [Table 1]provided below indicates a relationship between a system transmissionbandwidth and a channel bandwidth defined in the LTE system. Forexample, the LTE system having a channel bandwidth of 10 MHz may have atransmission bandwidth consisting of 50 RBs.

TABLE 1 Channel 1.4 3 5 10 15 20 bandwidth BW_(channel) [MHz]Transmission 6 15 25 50 75 100 bandwidth configuration N_(RB)

Downlink control information may be transmitted within first N OFDMsymbols in the subframe. Generally, N={1, 2, 3} in an embodiment.Accordingly, N may be variable for each subframe according to an amountof control information to be transmitted in the current subframe. Thedownlink control information to be transmitted may include a controlchannel transmission interval indicator indicating how many OFDM symbolsare used for transmitting the control information, schedulinginformation of downlink data or uplink data, and information on HARQACK/NACK.

In the LTE system, the scheduling information of downlink data or uplinkdata is transmitted from the eNB to the terminal through downlinkcontrol information (DCI). The DCI is defined in various formats. Thedetermined DCI format is applied and operated according to whether theDCI is scheduling information (UL grant) for uplink data or schedulinginformation (DL grant) for downlink data, whether the DCI is compact DCIhaving small size control information, whether the DCI applies spatialmultiplexing using multiple antennas, and whether the DCI is DCI forcontrolling power. For example, DCI format 1 which is scheduling controlinformation (DL grant) of downlink data may include one of pieces of thefollowing information.

-   -   Resource allocation type 0/1 flag: indicates whether a resource        allocation type is type 0 or type 1. Type 0 applies a bitmap        scheme and allocates resources in units of resource block groups        (RBGs). In the LTE system, a basic scheduling unit is a resource        block (RB) expressed by time and frequency domain resources, and        an RBG includes a plurality of RBs and is used as a basic        scheduling unit in the type 0 scheme. Type 1 allows allocation        of a predetermined RB in an RBG.    -   Resource block assignment: indicates RBs allocated to data        transmission. Expressed resources are determined according to        the system bandwidth and the resource allocation type.    -   Modulation and coding scheme (MCS): indicates a modulation        scheme used for data transmission and the size of a transport        block (TB) which is data to be transmitted.    -   HARQ process number: indicates a process number of HARQ.    -   New data indicator: indicates HARQ initial transmission or HARQ        retransmission.    -   Redundancy version: indicates a redundancy version of HARQ.    -   Transmit power control (TPC) command for physical uplink control        channel (PUCCH): indicates a transmission power control command        for a PUCCH which is an uplink control channel.

The DCI may be transmitted through a physical downlink control channel(PDCCH) or enhanced PDCCH (EPDCCH) which is a physical control channelvia a channel-coding and modulation process. Hereinafter, PDCCH orEPDCCH transmission may be interchangeable with DCI transmission throughthe PDCCH or the EPDCCH. Such a technology may be applied to otherchannels, and, for example, downlink data transmission may beinterchangeable with physical downlink shared channel (PDSCH)transmission.

In general, the DCI is scrambled with a particular radio networktemporary identifier (RNTI) (or a terminal identifier), independentlyfor each terminal, a cyclic redundancy check (CRC) bit is added thereto,and then channel coding is performed, whereby each independent PDCCH isconfigured and transmitted. In the time domain, the PDCCH is mapped andtransmitted during the control channel transmission interval. Themapping location of the PDCCH in the frequency domain may be determinedby an identifier (ID) of each terminal and distributed to the entiresystem transmission band.

Downlink data may be transmitted on the PDSCH which is a downlink datatransmission physical channel. The PDSCH may be transmitted after thecontrol channel transmission interval, and scheduling information suchas the detailed mapping location in the frequency domain and themodulation scheme is determined on the basis of the DCI transmittedthrough the PDCCH.

Via an MCS in the control information included in the DCI, the eNBreports the modulation scheme applied to the PDSCH to be transmitted tothe terminal and the size (transport block size (TBS)) of data to betransmitted. According to an embodiment, the MCS may include 5 bits orbits larger than or smaller than 5 bits. The TBS corresponds to the sizebefore channel coding for error correction is applied to the datatransport block to be transmitted by the eNB.

The modulation scheme supported by the LTE system includes QuadraturePhase Shift Keying (QPSK), 16 Quadrature Amplitude Modulation (16QAM),and 64QAM. Modulation orders (Qm) correspond to 2, 4, and 6respectively. That is, the eNB may transmit 2 bits per symbol in theQPSK modulation, 4 bits per symbol in the 16QAM, and 6 bits per symbolin the 64QAM. Further, a modulation scheme higher than or equal to 256QAM may be used according to system deformation.

FIG. 2 illustrates a basic structure of time-frequency domains which areradio resource domains in which data or a control channel is transmittedin uplink of the LTE system or a system similar thereto.

Referring to FIG. 2 , the horizontal axis indicates the time domain andthe vertical axis indicates the frequency domain. A minimum transmissionunit in the time domain is an SC-FDMA symbol, and one slot 206 consistsof N_(symb) SC-FDMA symbols 202. One subframe 205 consists of two slots.A minimum transmission unit in the frequency domain is a subcarrier, andthe bandwidth of the entire system transmission band consists of a totalof N_(BW) subcarriers 204. N_(BW) may have a value proportional to thesystem transmission band.

The basic unit of resources in the time-frequency domains is a resourceelement (RE) 212, and may be defined by an SC-FDMA symbol index and asubcarrier index. A resource block 208 may be defined by N_(symb)consecutive SC-FDMA symbols in the time domain and N_(RB) consecutivesubcarriers in the frequency domain. Accordingly, one RB consists ofN_(symb)×N_(RB) REs. In general, a minimum transmission unit of data orcontrol information is an RB unit. A PUCCH is mapped to a frequencydomain corresponding to 1 RB, and may be transmitted during onesubframe.

The timing relationship of a PUCCH or a PUSCH, which is an uplinkphysical channel for transmitting HARQ ACK/NACK corresponding to aPDSCH, which is a downlink data transmission physical channel, or aPDCCH or an EPDCCH including semi-persistent scheduling release (or SPSrelease) may be defined in the LTE system. For example, in the LTEsystem operating in FDD type, HARQ ACK/NACK corresponding to a PDSCHtransmitted in an (n−4)^(th) subframe or a PDCCH or an EPDCCH includingSRS release may be transmitted to a PUCCH or a PUSCH in an n^(th)subframe.

In the LTE system, a downlink HARQ adapts an asynchronous HARQ scheme inwhich a time point at which data is retransmitted is not fixed. That is,when the eNB receives a HARQ NACK feedback of data which the eNBinitially transmits from the terminal, the eNB freely determines thetime point at which retransmitted data is transmitted via a schedulingoperation. For the HARQ operation, the terminal may buffer data which isdetermined as an error on the basis of the result of decoding of thereceived data and then combine the data with the following retransmitteddata.

If the terminal receives a PDSCH including downlink data transmittedfrom the eNB through subframe n, the terminal transmits uplink controlinformation including HARQ ACK or NACK of the downlink data to the eNBthrough a PUCCH or a PUSCH in subframe n+k. In this instance, k may bedefined differently according to FDD or time division duplex (TDD) ofthe LTE system and a configuration the subframe. For example, in thecase of the FDD LTE system, k is fixed to 4. In the case of the TDD LTEsystem, k may be changed according to a subframe configuration and asubframe number. Further, when data is transmitted through a pluralityof carriers, k may be differently applied according to TDD configurationof each carrier.

In the LTE system, unlike downlink HARQ, uplink HARQ adapts asynchronous HARQ scheme in which a time point at which data istransmitted is fixed. That is, the uplink/downlink timing relationshipbetween a physical uplink shared channel (PUSCH), which is an uplinkdata transmission physical channel, and a PDCCH, which is a precedingdownlink control channel, and a physical hybrid indicator channel(PHICH), which is a physical channel for transmitting downlink HARQACK/NACK corresponding to uplink data on the PUSCH, may be determined bythe following rule.

If the terminal receives a PDCCH including uplink scheduling controlinformation transmitted from the eNB or a PHICH for transmittingdownlink HARQ ACK/NACK in subframe n, the terminal transmits uplink datacorresponding to the control information through a PUSCH in subframen+k. In this instance, k may be defined differently according to FDD orTDD of the LTE system, and a configuration thereof. For example, in thecase of the FDD LTE system, k may be fixed to 4. Meanwhile, in the caseof the TDD LTE system, k may be changed according to a subframeconfiguration and a subframe number. Further, when data is transmittedthrough a plurality of carriers, k may be differently applied accordingto TDD configuration of each carrier.

The terminal may receive a PHICH including information related todownlink HARQ ACK/NACK from the eNB in sub-frame i, and the PHICHcorresponds to a PUSCH transmitted by the UE in subframe i-k. In thisinstance, k is defined differently according to FDD or TDD of the LTEsystem, and a configuration thereof. For example, in the case of the FDDLTE system, k is fixed to 4. Meanwhile, in the case of the TDD LTEsystem, k may be changed according to a subframe configuration and asubframe number. Further, when data is transmitted through a pluralityof carriers, k may be differently applied according to TDD configurationof each carrier.

TABLE 2 Transmission scheme of Transmis- DCI PDSCH corresponding to sionmode format Search Space PDCCH Mode 1 DCI Common and Single-antennaport, port 0 (see format 1A UE specific by subclause 7.1.1) C-RNTI DCIUE specific by Single-antenna port, port 0 (see format 1 C-RNTIsubclause 7.1.1) Mode 2 DCI Common and Transmit diversity (see format 1AUE specific by subclause 7.1.2) C-RNTI DCI UE specific by Transmitdiversity (see format 1 C-RNTI subclause 7.1.2) Mode 3 DCI Common andTransmit diversity (see format 1A UE specific by subclause 7.1.2) C-RNTIDCI UE specific by Large delay CDD (see subclause format 2A C-RNTI7.1.3) or Transmit diversity (see subclause 7.1.2) Mode 4 DCI Common andTransmit diversity (see format 1A UE specific by subclause 7.1.2) C-RNTIDCI UE specific by Closed-loop spatial multiplexing format 2 C-RNTI (seesubclause 7.1.4)or Transmit diversity (see subclause 7.1.2) Mode 5 DCICommon and Transmit diversity (see format 1A UE specific by subclause7.1.2) C-RNTI DCI UE specific by Multi-user MIMO (see format 1D C-RNTIsubclause 7.1.5) Mode 6 DCI Common and Transmit diversity (see format 1AUE specific by subclause 7.1.2) C-RNTI DCI UE specific by Closed-loopspatial multiplexing format 1B C-RNTI (see subclause 7.1.4) using asingle transmission layer Mode 7 DCI Common and If the number of PBCHantenna format 1A UE specific by ports is one, Single-antenna C-RNTIport, port 0 is used (see subclause 7.1.1), otherwise Transmit diversity(see subclause 7.1.2) DCI UE specific by Single-antenna port; port 5(see format 1 C-RNTI subclause 7.1.1) Mode 8 DCI Common and If thenumber of PBCH antenna format 1A UE specific by ports is one,Single-antenna C-RNTI port, port 0 is used (see subclause 7.1.1),otherwise Transmit diversity (see subclause 7.1.2) DCI UE specific byDual layer transmission; port 7 format 2B C-RNTI and 8 (see subclause7.1.5A) or single-antenna port; port 7 or 8 (see subclause 7.1.1)

[Table 2] above shows supportable DCI formats according to eachtransmission mode in a condition set by a C-RNTI in 3GPP TS 36.213. Theterminal assumes the existence of the corresponding DCI format in acontrol area interval according to a preset transmission mode andperforms a search and decoding. For example, if transmission mode 8 isindicated to the terminal, the terminal searches for DCI format 1A in acommon search space and a UE-specific search space and searches for DCIformat 2B only in the UE-specific search space.

The descriptions about the wireless communication system is providedfrom the perspective of the LTE system, and the disclosure is notlimited to the LTE system and may be applied to various wirelesscommunication systems such as NR, 5G, or the like. Further, if theembodiment of the disclosure is applied to another wirelesscommunication system, the k value may also be changed in a system usinga modulation scheme corresponding to FDD.

In a communication and broadcasting system, link performance maysignificantly deteriorate due to various channel noise, fadingphenomenon, and inter-symbol interference (ISI). Accordingly, in orderto realize high-speed digital communication and broadcasting systemsthat require high data throughput and high reliability such asnext-generation mobile communication, digital broadcasting, and portableInternet, there is a need to develop a technology for removing noise,fading, and inter-symbol interference. As research on noise removal,research on an error correcting code is actively performed recently fora method of increasing reliability of communication by efficientlyreconstructing distortion of information.

The disclosure provides a method and an apparatus for transmitting acoding bit which may support various input lengths and code rates.Further, the disclosure provides a method of configuring a base graph ofan LDPC code used for data channel transmission and a method and anapparatus for segmenting a transport block using the LDPC code.

Subsequently, a low density parity check (LDPC) code will be described.

The LDPC code is a type of linear block codes, and a process ofdetermining a codeword that satisfies a condition such as [Equation 1]below is included.

$\begin{matrix}{{H \cdot c^{T}} = {{\left\lbrack {h_{1}h_{2}h_{3}\ldots\ h_{N_{ldpc} - 1}} \right\rbrack \cdot c^{T}} = {\sum\limits_{i = 0}^{N_{ldpc}}{c_{i} \cdot h_{i}}}}} & \left\lbrack {{Equation}1} \right\rbrack\end{matrix}$

c=[c₀, c₁, c₂, . . . , c_(N) _(ldpc) −1] in [Equation 1].

In [Equation 1], H denotes a parity check matrix, C denotes a codeword,c_(i) denotes an i^(th) bit of a codeword, and N_(ldpc) denotes acodeword length. Here, h_(i) denotes an i^(th) column of the paritycheck matrix (H).

The parity check matrix H includes N_(ldpc) columns, the N_(ldpc) beingthe same as the number of bits of the LDPC codeword. [Equation 1] meansthat a sum of the products of i^(th) columns (h_(i)) of the parity checkmatrix and i^(th) codeword bits c_(i) is “0”, so that the i^(th) column(h_(i)) is relevant to the i^(th) codeword bit c_(i).

For the parity check matrix used in the communication and broadcastingsystem, a quasi-cyclic LDPC code (or a QC-LDPC code, hereinafter,referred to as the QC-LDPC code) generally using a quasi-cyclic paritycheck matrix is frequently used for easy implementation.

The QC-LDPC code features a parity check matrix including a 0-matrix(zero matrix) having a square matrix form or a circulant permutationmatrix.

As shown in [Equation 2], a permutation matrix P (P_(ij)) having thesize of Z×Z is defined.

$\begin{matrix}{P_{i,j} = \left\{ \begin{matrix}{{{1{if}i} + 1} \equiv {j{mod}\ Z}} \\{0{otherwise}}\end{matrix} \right.} & \left\lbrack {{Equation}2} \right\rbrack\end{matrix}$

In [Equation 2], P_(ij) (0≤i, j<Z) is an element (entry) in an i^(th)row and a j^(th) column in the matrix P. On the basis of 0≤i<Z for thepermutation matrix described above, it may be noted that P is acirculant permutation matrix obtained by circularly shifting eachelement of an identity matrix having the size of Z×Z to the right by i.

The parity check matrix H of the simplest QC-LDPC code may be indicatedas shown in [Table 3] below.

$\begin{matrix}{H = \begin{bmatrix}P^{a_{11}} & P^{a_{12}} & \ldots & P^{a_{1n}} \\P^{a_{21}} & P^{a_{22}} & \ldots & P^{a_{2n}} \\ \vdots & \vdots & \ddots & \vdots \\P^{a_{m1}} & P^{a_{m2}} & \ldots & P^{a_{mn}}\end{bmatrix}} & \left\lbrack {{Equation}3} \right\rbrack\end{matrix}$

If P⁻¹ is defined as a 0-matrix having the size of Z×Z, each exponenta_(ij) of the circulant permutation matrix or the 0-matrix has one ofthe values {−1, 0, 1, 2, . . . , Z−1} in [Equation 3] above. Further, itmay be noted that the parity check matrix H of [Equation 3] has the sizeof mZ×nZ since it has n column blocks and m row blocks.

In general, a binary matrix having the size of m×n obtained by replacingthe circulant permutation matrix and the 0-matrix in the parity checkmatrix of [Equation 3] with 1 and 0 is determined as a mother matrix (ora base graph) of the parity check matrix H, and a matrix of integershaving the size of m×n obtained by selecting only exponents of thecirculant permutation matrix or the 0-matrix as shown in [Equation 4]below is determined as an exponent matrix E(H) of the parity checkmatrix H.

$\begin{matrix}{{E(H)} = \begin{bmatrix}a_{11} & a_{12} & \ldots & a_{1n} \\a_{21} & a_{22} & \ldots & a_{2n} \\ \vdots & \vdots & \ddots & \vdots \\a_{m1} & a_{m2} & \ldots & a_{mn}\end{bmatrix}} & \left\lbrack {{Equation}4} \right\rbrack\end{matrix}$

Meanwhile, the performance of an LDPC code may be determined accordingto the parity check matrix. Accordingly, it is required to design anefficient parity check matrix for an LDPC code having excellentperformance. Further, an LDPC encoding and decoding method forsupporting various input lengths and code rates is needed.

A method known as lifting is used for efficient design of the QC-LDPCcode. The lifting is a method of efficiently designing a very largeparity check matrix by configuring a Z value for determining the size ofa circulant permutation matrix or a 0-matrix from a given small mothermatrix according to a specific rule. The conventional lifting method anda characteristic of the QC-LDPC code designed through the lifting arebriefly described below.

If an LDPC code C₀ is given, S QC-LDPC codes to be designed through thelifting method are C₁, C₂, . . . , C_(k), . . . , and C_(S) (similarly,C_(k) for 1≤k≤S), a parity check matrix of the QC-LDPC code C_(k) isH_(k), and a value corresponding to the size of row blocks and columnblocks of the circulant matrix included in the parity check matrix isZ_(k). C₀ corresponds to the smallest LDPC code having a mother matrixof c₁, . . . , and C_(S) codes as a parity check matrix, a Z₀ valuecorresponding to the size of row blocks and column blocks is 1, andZ_(k)<Z_(k+1) for 0≤k≤S−1. For convenience, a parity check matrix H_(k)of each code C_(k) has an exponent matrix E(H_(k)))=a_(i,j) ^((k))having the size of m×n, and one of the values {−1, 0, 1, 2, . . . ,Z_(k)−1} is selected as each exponent a_(i,j) ^((k)). The liftingincludes steps of C₀→_(c1)→ . . . →C_(S) and featuresZ_(k+1)=q_(k+1)Z_(k) (q_(k+1) is a positive integer, k=0,1, . . . ,S−1). If only the parity check matrix HS of the C_(S) is stored by acharacteristic of the lifting process, all the QC-LDPC codes C₀, c₁, . .. , C_(S) can be indicated using [Equation 5] or [Equation 6] belowaccording to the lifting method.

$\begin{matrix}{{E\left( H_{k} \right)} \equiv \left\lfloor {\frac{Z_{k}}{Z_{S}}{E\left( H_{S} \right)}} \right\rfloor} & \left\lbrack {{Equation}5} \right\rbrack\end{matrix}$ $\begin{matrix}{{E\left( H_{k} \right)} \equiv {{E\left( H_{S} \right)}{mod}\ Z_{k}}} & \left\lbrack {{Equation}6} \right\rbrack\end{matrix}$

[Equation 7] is a most generalized expression of the method.P _(ij) =f(V _(ij) ,Z)  [Equation 7]

In [Equation 7], f(x,y) is a predetermined function having x and y asinput values. V_(i,j) is an element corresponding to an i^(th) row and aj^(th) column of an exponent matrix of the parity check matrixcorresponding to the largest LDPC code (for example, corresponding tothe CS in the above description). P_(ij) is an element corresponding toan i^(th) row and a j^(th) column of an exponent matrix of the paritycheck matrix corresponding to the LDPC code having a predetermined size(for example, corresponding to the C_(k) in the above description), andZ is the size of row blocks and column blocks of the circulant matrixincluded in the parity check matrix of the corresponding LDPC code.Accordingly, if V_(i,j) is defined, a parity check matrix for an LDPCcode having a predetermined size can be defined.

In a description of the disclosure later, the above-described symbolsare named, defined, and used as follows.

[Definition 1]

E(H_(S)): maximum exponent matrix

V_(ij): maximum exponent matrix element (corresponding to an (i,j)^(th)element of E(H_(S))

A parity check matrix for a predetermined LDPC code may be indicatedusing the above-defined maximum exponent matrix or maximum exponentmatrix element.

In a next-generation mobile communication system, there may be aplurality of maximum exponent matrixes defined above in order toguarantee the best performance of a code block having various lengths.For example, there may be M different maximum exponent matrices, whichmay be expressed as follows.E(H _(S))₁ ,E(H _(S))₂ , . . . E(H _(S))_(M)  [Equation 8]

There may be a plurality of maximum exponent matrix elementscorresponding thereto, which may be expressed as follows.(V _(i,j))₁,(V _(i,j))₂, . . . , (V _(i,j))_(M)[Equation 9]

In [Equation 9], a maximum exponent matrix element (V_(i,j))_(m)corresponds to (i, j) of a maximum exponent matrix E(H_(S))_(m).Hereinafter, in definition of the parity check matrix for the LDPC code,the above-defined maximum exponent matrix will be used and described.This may be applied to be the same as the expression using the maximumexponent matrix element.

A turbo code-based code block segmentation and CRC attachment method ina document of LTE TS 36.213 is described.

5.1.2 Code Block Segmentation and Code Block CRC Attachment

The input bit sequence to the code block segmentation is denoted by b₀,b₁, b₂, b₃, . . . , b_(B-1), where B>0. If B is larger than the maximumcode block size Z, segmentation of the input bit sequence is performedand an additional CRC sequence of L=24 bits is attached to each codeblock. The maximum code block size is:

-   -   Z=6144.

If the number of filler bits F calculated below is not 0, filler bitsare added to the beginning of the first block.

-   -   Note that if B<40, filler bits are added to the beginning of the        code block.

The filler bits shall be set to <NULL> at the input to the encoder.

Total number of code blocks C is determined by:

  if B ≤ Z    L = 0    Number of code blocks: C = 1    B′ = B   else   L = 24    Number of code blocks: C = ┌B /(Z − L)┐.    B′ = B + C · L  end if

The bits output from code block segmentation, for C≠0, are denoted byc_(r0), c_(r1), c_(r2), c_(r3), . . . , c_(r(K) _(r) ⁻¹⁾ where r is thecode block number, and K_(r) is the number of bits for the code blocknumber r.

-   -   Number of bits in each code block (applicable for C≠0 only):    -   First segmentation size: K₊ minimum K in table 5.1.3-3 such that        C·K≥B′

  if C = 1      the number of code blocks with length K₊ is C₊ = 1, K⁻ =0, C⁻ = 0   else if C > 1      Second segmentation size: K⁻ = maximum Kin table 5.1.3-3 such that K < K₊      Δ_(K) = K₊ − K⁻    Number ofsegments of size K⁻:$C_{-} = {\left\lfloor \frac{{C \cdot K_{+}} - B^{\prime}}{\Delta_{K}} \right\rfloor.}$   Number of segments of size K₊: C₊ = C − C⁻.   end if  Number offiller bits: F = C₊ · K₊ + C⁻ · K⁻ − B′  for k = 0 to F-1 -- Insertionof filler bits   c_(0k) = <NULL>  end for  k = F  s = 0  for r = 0 toC-1   if r < C⁻      K_(r) = K⁻    else      K_(r) = K₊   end if   while k < K_(r) − L      c_(rk) = b_(s)      k = k + 1      s = s + 1   end while    if C >1    The sequence c_(r0), c_(r1), c_(r2), c_(r3),. . . , c_(r(K) _(r) _(−L-1)) is used to calculate the CRC parity bits   p_(r0), p_(r1), p_(r2), . . . , p_(r(L-1)) according to section 5.1.1with the generator polynomial    g_(CRC24B)(D). For CRC calculation itis assumed that filler bits, if present, have the    value 0.    while k< K_(r)     c_(rk) = p_(r(k+L−K) _(r) ₎     k = k + 1    end while   endif   k = 0 end for

5G and next-generation communication systems use the LDPC code in a datachannel unlike the LTE system. Even in a situation in which the LDPCcode is applied, one transport block may be divided into a plurality ofcode blocks, and some code blocks thereof may form one code block group.Further, the numbers of code blocks of respective code block groups maybe the same as each other or may have different values. Bit-unitinterleaving may be applied to an individual code block, a code blockgroup, or a transport block.

FIG. 3 illustrates a basic structure of a mother matrix (or a basegraph) of the LDPC code.

In FIG. 3 , two basic structures of a base graph 300 of the LDPC codesupporting a data channel coding are basically supported by anext-generation mobile communication system. The first base graphstructure of the LDPC code is a matrix structure having a maximumvertical length 320 of 46 and a maximum horizontal length 318 of 68, andthe second base graph structure of the LDPC code is a matrix structurehaving a maximum vertical length 320 of 42 and a maximum horizontallength 318 of 52. The first base graph structure of the LPDC code maysupport a minimum of 1/3 code rate to a maximum of 8/9 code rate, andthe second base graph structure of the LDPC may support a minimum of 1/5code rate to a maximum of 8/9 code rate.

Basically, the LDPC code may include 6 sub matrix structures. A firstsub matrix structure 302 includes system bits. A second sub matrixstructure 304 is a square matrix and includes parity bits. A third submatrix structure 306 is a zero matrix. A fourth sub matrix structure 308and a fifth sub matrix structure 310 include parity bits. A sixth submatrix structure 312 is a unit matrix.

In the first base graph structure of the LDPC code, a horizontal length322 of the first sub matrix 302 has a value of 22 and a vertical length314 has a value of 4 or 5. Both a horizontal length 324 and a verticallength 314 of the second sub matrix 304 have a value of 4 or 5. Ahorizontal length 326 of the third sub matrix 306 has a value of 42 or41 and a vertical length 314 has a value of 4 or 5. A vertical length316 of the fourth sub matrix 308 has a value of 42 or 41 and ahorizontal length 322 has a value of 22. A horizontal length 324 of thefifth sub matrix 310 has a value of 4 or 5 and a vertical length 316 hasa value of 42 or 41. Both a horizontal length 326 and a vertical length316 of the sixth sub matrix 312 have a value of 42 or 31.

In the second base graph structure of the LDPC code, a horizontal length322 of the first sub matrix 302 has a value of 10 and a vertical length314 has a value of 7. Both a horizontal length 324 and a vertical length314 of the second sub matrix 304 have a value of 7. A horizontal length326 of the third sub matrix 306 has a value of 35 and a vertical length314 has a value of 7. A vertical length 316 of the fourth sub matrix 308has a value of 35 and a horizontal length 322 has a value of 10. Ahorizontal length 324 of the fifth sub matrix 310 has a value of 7 and avertical length 316 has a value of 35. Both a horizontal length 326 anda vertical length 316 of the sixth sub matrix 312 have a value of 35.

One code block size supportable by the first base graph structure of theLDPC code is 22×Z (Z=a×2j and Z is as shown in [Table 3] below. Amaximum size of one supportable code block is 8448 and a minimum size ofone supportable code block is 44. For reference, some or all of 272,304, 336, 368) may be additionally reflected as a candidate of Z in[Table 3]).

TABLE 3 a Z 2 3 5 7 9 11 13 15 j 0 2 3 5 7 9 11 13 15 1 4 6 10 14 18 2226 30 2 8 12 20 28 36 44 52 60 3 16 24 40 56 72 88 104 120 4 32 48 80112 144 176 208 240 5 64 96 160 224 288 352 6 128 192 320 7 256 384

In the first base graph structure of the LDPC code, sizes of onesupportable code block are as follows.

44, 66, 88, 110, 132, 154, 176, 198, 220, 242, 264, 286, 308, 330, 352,296, 440, 484, 528, 572, 616, 660, 704, 792, 880, 968, 1056, 1144, 1232,1320, 1408, 1584, 1760, 1936, 2112, 2288, 2464, 2640, 2816, 3168, 3520,3872, 4224, 4576, 4928, 5280, 5632, 6336, 7040, 7744, 8448, (5984, 6688,7392, 8096)

In the above sizes, (5984, 6688, 7392, 8096) may be additionallyincluded.

A total of M maximum exponent matrices E(H_(S))_(i) ¹ are additionallydefined on the basis of the first base graph of the LDPC code (BG #1).In general, M may have a value of 8 or a random natural value, and i hasa value from 1 to M. The terminal performs downlink data decoding oruplink data encoding using the matrices E(H_(S))_(i) ¹. The matricesE(H_(S))_(i) ¹ have particular element values shifted from the firstbase graph of the LDPC code (BG #1). That is, the matrices E(H_(S))_(i)¹ may have different shifted values.

In the second base graph structure of the LDPC code, one supportablecode block size is 10×Z (Z=a×2 and Z is as shown in [Table 4] below. Amaximum size of one supportable code block is 2560 (or 3840) and aminimum size of one supportable code block is 20. For reference, some orall of (288, 272, 304, 320, 336, 352, 368, 384) may be additionallyreflected as a candidate of Z in [Table 4].

TABLE 4 a Z 2 3 5 7 9 11 13 15 j 0 2 3 5 7 9 11 13 15 1 4 6 10 14 18 2226 30 2 8 12 20 28 36 44 52 60 3 16 24 40 56 72 88 104 120 4 32 48 80112 144 176 208 240 5 64 96 160 224 6 128 192 7 256

In the second base graph structure of the LDPC code, sizes of onesupportable code block are as follows.

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040, 1120, 1200, 1280, 1440, 1600, 1760, 1920,2080, 2240, 2400, 2560 (2880, 3200, 3520, 3840, 2720, 3040, 3360, 3680)

In the above sizes, (2880, 3200, 3520, 3840, 2720, 3040, 3360, 3680) arevalues that may be additionally included.

A total of M maximum exponent matrices E(H_(S))_(i) ² are additionallydefined on the basis of the second base graph of the LDPC code (BG #2).In general, M may have a value of 8 or a random natural value, and i hasa value from 1 to M. The terminal performs downlink data decoding oruplink data encoding using the matrices E(H_(S))_(i) ². The matricesE(H_(S))_(i) ² have particular element values shifted from the secondbase graph of the LDPC code (BG #2). That is, the matrices E(H_(S))_(i)² may have different shifted values.

As described above, the two types of base graphs are provided in thenext-generation mobile communication system. Accordingly, particularterminals may support only the first base graph or the second basegraph, or there may be terminals supporting both the two base graphs.They are listed as shown in [Table 5] below.

TABLE 5 Terminal type Supportable operation Type 1 Support only firstbase graph or support maximum exponent matrix E(H_(S))¹ _(i) Type 2Support only second base graph or support maximum exponent matrixE(H_(S))² _(i) Type 3 Support both two base graphs or support maximumexponent matrices E(H_(S))¹ _(i) and E(H_(S))² _(i)

When receiving downlink data information through downlink controlinformation from the eNB, the terminal supporting type 1 determines thata base graph applied to a transport block including the downlink datainformation is always the first base graph and applies the maximumexponent matrix E(H_(S))_(i) ¹ to data encoding or decoding. Whenreceiving downlink data information through downlink control informationfrom the eNB, the terminal supporting type 2 determines that a basegraph applied to a transport block including the downlink datainformation is always the second base graph and applies the maximumexponent matrix E(H_(S))_(i) ² to data encoding or decoding.

When receiving downlink data information through downlink controlinformation from the eNB, the terminal supporting type 3 receives inadvance a configuration of a base graph applied to a transport blockincluding the downlink data information from the eNB through higherlayer signaling such as SIB, RRC, or MAC CE or through downlink controlinformation transmitted in a UE group-common, UE (cell)-common orUE-specific control channel. The downlink control information may beincluded together with transport block scheduling information or alone.

Embodiment 1-1

FIG. 4 is a block diagram illustrating a reception process of theterminal according to an embodiment of the disclosure.

In FIG. 4 , the terminal receives downlink control information throughUE (cell) common downlink control channel, a UE group-common downlinkcontrol channel, or a UE-specific downlink control channel in step 400.

The terminal determines whether the received downlink controlinformation corresponds to one or a combination of two or more of thefollowing conditions in step 410.

A. An RATI scrambled in CRC of the downlink control information

B. Size of a transport block included in the downlink controlinformation

C. A base graph indicator included in the downlink control information

D. A Scheduling-related value included in the downlink controlinformation

If the RNTI scrambled in the CRC of the downlink control information,which is condition A, is an RNTI (for example, a semi-persistentscheduling (SPS)-RNTI) or a cell-RNTI (C-RNTI)) other than a randomaccess (RA)-RNTI, a paging-RNTI (P-RNTI), a system information(SI)-RNTI, a single cell (SC)-RNTI, a group-RNTI (G-RNTI), the terminaldetermines that it corresponds to condition 1 and performs operation 1in step 420.

If the RNTI scrambled in the CRC of the downlink control information,which is condition A, is an RA-RNTI, a P-RNTI, an SI-RNTI, an SC-RNTI,or a G-RNTI, the terminal determines that it corresponds to condition 2and performs operation 2 in step 430.

If the size of the transport block included in the downlink controlinformation, which is condition B, and the CRC is larger than or equalto a predetermined threshold value (Δ1), the terminal determines that itcorresponds to condition 1 and performs operation 1 in step 420.

If the size of the transport block included in the downlink controlinformation, which is condition B, and the CRC is equal to or smallerthan a predetermined threshold value (Δ2), the terminal determines thatit corresponds to condition 2 and performs operation 2 in step 430.

The threshold value (Δ1) or the threshold value (Δ2) may be a valuefixed to 2560 (or 3840, 960, 1040, 1120, 170, 640, or a predeterminedvalue). Further, the threshold value (Δ1) or the threshold value (Δ2)may be the same value or different values.

Alternatively, the threshold value (Δ1) or the threshold value (Δ2) maybe a value configured in advance through higher layer signaling such asSIB, RRC, or MAC CE or a value configured through downlink controlinformation of a UE group-common, UE-common, or UE-specific controlchannel. At this time, before the threshold value (Δ) is configured, avalue fixed to 2560 (or 3840, 960, 1040, 1120, 170, 640, or otherpredetermined values) may be used as a default threshold value (Δ). Atime point at which the threshold value (Δ1) or the threshold value (Δ2)is configured means a time point before the terminal scrambles CRC ofdownlink control information with an RA-RANTI, a P-RNTI, an SI-RNTI, anSC-RNTI, or a G-RNTI.

Alternatively, if the size of the transport block included in thedownlink control information, which is condition B, and the CRC issmaller than 2560 (or 3840) (and larger than 160 or 640) and if aminimum code block length (K_(min)) among code block lengths (K)supportable by the first base graph that satisfies K>(transport blocksize+CRC size) and code block lengths (K) supportable by the second basegraph belongs to the first base graph, the terminal determines that itcorresponds to condition 1 and performs operation 1 in step 420.

Alternatively, if the size of the transport block included in thedownlink control information, which is condition B, and the CRC issmaller than 2560 (or 3840) (and larger than 160 or 640) and if aminimum code block length K among code block lengths supportable by thefirst base graph that satisfies K>(transport block size+ CRC size) andcode block lengths (K) supportable by the second base graph belongs tothe second base graph, the terminal determines that it corresponds tocondition 2 and performs operation 2 in step 430.

This may be expressed using the following equation.(TB+CRC)≤K≤V ₂ where K∈K ¹ or K∈K ²K*=min(K)

If K*∈K¹, satisfy condition 1 and perform operation 1 in step 420

If K*∈K², satisfy condition 2 and perform operation 2 in step 430

K is a code block length, K* is a selected code block length, and TB isa transport block size. Further, the CRC is a CRC size, K¹ is a set ofcode block lengths supportable by the first base graph, and K² is a setof code block lengths supportable by the second base graph.

Alternatively, they may be expressed using the following equation.V1=(TB+CRC)<K<V2 where K∈K1 or K∈K2K*=min(K)

If K*∈K¹, satisfy condition 1 and perform operation 1 in step 420

If K*∈K², satisfy condition 2 and perform operation 2 in step 430

K is a code block length, K* is a selected code block length, and TB isa transport block size. Further, the CRC is a CRC size, K¹ is a set ofcode block lengths supportable by the first base graph, and K² is a setof code block lengths supportable by the second base graph.

K¹ is a set of code block lengths supportable by the first base graph(or the maximum exponent matrix E(H_(S))_(i) ¹), and the type of setsmay be one or a combination of two or more of the following values. V₁may be 160, 640, or another value. V₂ may be 2560, 3840, 960, 1040,1120, or another value.

Alternatively, if TB+CRC is smaller than V₁ in the above equation,decoding or encoding can be performed by applying one of the maximumexponent matrices E(H_(S))_(i) ². If TB+CRC is larger than V₂ in theabove equation, decoding or encoding can be performed by applying one ofthe maximum exponent matrices E(H_(S))_(i) ¹.

K¹ is a set of code block lengths supportable by the first base graph(or the maximum exponent matrix E(H_(S))_(i) ¹), and the type of setsmay be one or a combination of two or more of the following values.

1. The case in which K is equal to or smaller than 2560

44, 66, 88, 132, 154, 176, 198, 242, 264, 286, 308, 330, 352, 296, 484,528, 572, 616, 660, 704, 792, 968, 1056, 1144, 1232, 1320, 1408, 1584,1936, 2112, 2288, 2464

2. The case in which K is equal to or smaller than 3840

44, 66, 88, 132, 154, 176, 198, 242, 264, 286, 308, 330, 352, 296, 484,528, 572, 616, 660, 704, 792, 968, 1056, 1144, 1232, 1320, 1408, 1584,1936, 2112, 2288, 2464, 2640, 2816, 3168, 3520

3. The case in which K is equal to or smaller than 960

44, 66, 88, 132, 154, 176, 198, 242, 264, 286, 308, 330, 352, 296, 484,528, 572, 616, 660, 704, 792

4. The case in which K is equal to or smaller than 1040

44, 66, 88, 132, 154, 176, 198, 242, 264, 286, 308, 330, 352, 296, 484,528, 572, 616, 660, 704, 792, 968

5. The case in which K is equal to or smaller than 1120

44, 66, 88, 132, 154, 176, 198, 242, 264, 286, 308, 330, 352, 296, 484,528, 572, 616, 660, 704, 792, 968, 1056

If the values in the table are equal to or smaller than M, all or someof the values can be generally used while being omitted from the table.160, 640, or another value may be selected as M.

K² is a set of code block lengths supportable by the second base graph(or the maximum exponent matrix E(H_(S))_(i) ²), and the type of setsmay be one or a combination of two or more of the following values.

1. The case in which K is equal to or smaller than 2560

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040, 1120, 1200, 1280, 1440, 1600, 1760, 1920,2080, 2240, 2400, 2560

2. The case in which K is equal to or smaller than 3840

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040, 1120, 1200, 1280, 1440, 1600, 1760, 1920,2080, 2240, 2400, 2560, (2720, 2880, 3040, 3200, 3360, 3520, 3680, 3840)

3. The case in which K is equal to or smaller than 960

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960

4. The case in which K is equal to or smaller than 1040

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040

5. The case in which K is equal to or smaller than 1120

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040, 1120

If the base graph indicator included in the downlink controlinformation, which is condition C, indicates a value of 0 (or 1), theterminal determines that it satisfies condition 1 and performs operation1 in step 420.

If the base graph indicator included in the downlink controlinformation, which is condition C, indicates a value of 1 (or 0), theterminal determines that it satisfies condition 2 and performs operation2 in step 430.

If MCS, RV, NDI, or frequency or time resource allocation values amongthe scheduling-related values included in the downlink controlinformation, which are condition D, indicate specific information, theterminal determines that it corresponds to condition 1 and performsoperation 1 in step 420.

If MCS, RV, NDI, or frequency or time resource allocation values amongthe scheduling-related values included in the downlink controlinformation, which are condition D, indicate specific information, theterminal determines that it corresponds to condition 2 and performsoperation 2 in step 430.

If the terminal performs operation 1, the terminal performs one or acombination of two or more of operations.

1. The terminal attempts decoding on a transport block indicated by thedownlink control information on the basis of code block lengthssupportable by the first base graph (or the maximum exponent matrixE(H_(S))_(i) ¹.

2. The terminal attempts decoding on a transport block indicated by thedownlink control information on the basis of the following table ofsupportable code blocks.

44, 66, 88, 110, 132, 154, 176, 198, 220, 242, 264, 286, 308, 330, 352,296, 440, 484, 528, 572, 616, 660, 704, 792, 880, 968, 1056, 1144, 1232,1320, 1408, 1584, 1760, 1936, 2112, 2288, 2464, 2640, 2816, 3168, 3520,3872, 4224, 4576, 4928, 5280, 5632, 6336, 7040, 7744, 8448, (5984, 6688,7392, 8096)

3. Among the following available code block sets, one or morecombinations thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₁ ¹. For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₁¹ supported by the first base graph.

A. 44, 88, 176, 352, 704, 1408, 2816, 5632

B. 44, 66, 110, 154, 198, 242, 286, 330

C. 44, 66, 154, 198, 242, 286, 330

4. Among the following available code block sets, one or morecombinations thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₂ ¹. For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₂¹ supported by the first base graph.

A. 66, 132, 264, 528, 1056, 2112, 4224, 8448

B. 88, 132, 220, 308, 396, 484, 572, 660

C. 88, 132, 308, 396, 484, 572, 660

5. Among the following available code block sets, one or morecombinations) thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₃ ¹. For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₃¹ supported by the first base graph.

A. 110, 220, 440, 880, 1760, 3520, 7040

B. 176, 264, 440, 616, 792, 968, 1144, 1320

C. 1760, 3520, 7040

D. 3520, 7040

E. 7040

F. 176, 264, 616, 792, 968, 1144, 1320

6. Among the following available code block sets, one or morecombinations thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₄ ¹ For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₄¹ supported by the first base graph.

A. 154, 308, 616, 1232, 2464, 4928

B. 352, 528, 880, 1232, 1584, 1936, 2288, 2640

C. 352, 528, 1232, 1584, 1936, 2288, 2640

7. Among the following available code block sets, one or morecombinations) thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₅ ¹.

For the corresponding code blocks, the terminal at least attemptsdecoding on a transport block indicated by the downlink controlinformation on the basis of the matrix E(H_(S))₅ ¹ supported by thefirst base graph.

A. 198, 396, 792, 1584, 3168, 6336

B. 704, 1056, 1760, 2464, 3168, 3872, 4576, 5280

C. 704, 1056, 2464, 3168, 3872, 4576, 5280

8. Among the following available code block sets, one or morecombinations) thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₆ ¹. For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₆¹ supported by the first base graph.

A. 242, 484, 968, 1936, 3872

B. 1408, 2112, 3520, 4928, 6336, 7744

C. 1408, 2112, 4928, 6336, 7744

9. Among the following available code block sets, one or morecombinations thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₇ ¹. For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₇¹ supported by the first base graph.

A. 286, 572, 1144, 2288, 4576

B. 2816, 4224, 7040

10. Among the following available code block sets, one or morecombinations) thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₈ ¹. For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₈¹ supported by the first base graph.

A. 330, 660, 1320, 2640, 5280

B. 5632, 8448

If the terminal performs operation 2, the terminal performs one or acombination of two or more of the following operations.

1. The terminal attempts decoding on a transport block indicated by thedownlink control information on the basis of code block lengthssupportable by the second base graph.

2. The terminal attempts decoding on a transport block indicated by thedownlink control information on the basis of the following table ofsupportable code blocks.

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040, 1120, 1200, 1280, 1440, 1600, 1760, 1920,2080, 2240, 2400, 2560 (2880, 3200, 3520, 3840, 2720, 3040, 3360, 3680)

3. Among the following available code block sets, one or morecombinations) thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₁ ². For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₁² supported by the second base graph.

A. 20, 40, 80, 160, 320, 640, 1280

B. 20, 30, 50, 70, 90, 110, 130, 150

4. Among the following available code block sets, one or morecombinations) thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₂ ². For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₂² supported by the second base graph.

A. 30, 60, 120, 240, 480, 960, 1920, (3840)

B. 40, 60, 100, 140, 180, 220, 260, 300

5. Among the following available code block sets, one or morecombinations) thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₃ ². For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₃² supported by the second base graph.

A. 50, 100, 200, 400, 800, 1600, (3200)

B. 80, 120, 200, 280, 360, 440, 520, 600

6. Among the following available code block sets, one or morecombinations thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₄ ². For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₄² supported by the second base graph.

A. 70, 140, 280, 560, 1120, 2240

B. 160, 240, 400, 560, 720, 880, 1040, 1200

7. Among the following available code block sets, one or morecombinations) thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₅ ². For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₅² supported by the second base graph.

A. 90, 180, 360, 720, 1440, (2880)

B. 320, 480, 800, 1120, 1440, 1760, 2080, 2400

8. Among the following available code block sets, one or morecombinations thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₆ ². For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₆² supported by the second base graph.

A. 110, 220, 440, 880, 1760, (3520)

B. 640, 960, 1600, 2240, (2880), (3520)

9. Among the following available code block sets, one or morecombinations thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₇ ². For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₇² supported by the second base graph.

A. 130, 260, 520, 1040, 2080

B. 1280, 1920, (3200)

10. Among the following available code block sets, one or morecombinations thereof correspond to code blocks which the terminalencodes or decodes using E(H_(S))₈ ². For the corresponding code blocks,the terminal at least attempts decoding on a transport block indicatedby the downlink control information on the basis of the matrix E(H_(S))₈² supported by the second base graph.

A. 150, 300, 600, 1200, 2400

B. 2560, (3840)

In the disclosure, a number in brackets means that the correspondingvalue is included or not.

Embodiment 1-2

FIG. 5 is a block diagram illustrating a reception operation of theterminal according to embodiment 1-2.

In FIG. 5 , the terminal receives downlink control information throughUE (cell) common downlink control channel, a UE group-common downlinkcontrol channel, or a UE-specific downlink control channel in step 500.

The terminal performs decoding of a transport block in a downlink datachannel allocated through reception of the downlink control informationaccording to one or a combination of two or more of the followingoperations in step 510.

1. The terminal encodes or decodes the corresponding transport block byapplying one of the maximum exponent matrices E(H_(S))_(i) ¹ inconsideration of the following supportable code block lengths.

44, 66, 88, 110, 132, 154, 176, 198, 220, 242, 264, 286, 308, 330, 352,296, 440, 484, 528, 572, 616, 660, 704, 792, 880, 968, 1056, 1144, 1232,1320, 1408, 1584, 1760, 1936, 2112, 2288, 2464, 2640, 2816, 3168, 3520,3872, 4224, 4576, 4928, 5280, 5632, 6336, 7040, 7744, 8448, (5984, 6688,7392, 8096)

2. The terminal encodes or decodes the corresponding transport block byapplying one of the maximum exponent matrices E(H_(S))_(i) ² inconsideration of the following supportable code block lengths.

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040, 1120, 1200, 1280, 1440, 1600, 1760, 1920,2080, 2240, 2400, 2560, (2880, 3200, 3520, 3840, 2720, 3040, 3360, 3680)

3. The terminal encodes or decodes the corresponding transport block byapplying one of the maximum exponent matrices E(H_(S))_(i) ¹ orE(H_(S))_(i) ² in consideration of the following supportable code blocklengths.

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040, 1120, 1200, 1280, 1440, 1600, 1760, 1920,2080, 2240, 2400, 2560, 2640, 2816, 3168, 3520, 3872, 4224, 4576, 4928,5280, 5632, 6336, 7040, 7744, 8448, (5984, 6688, 7392, 8096)

4. The terminal encodes or decodes the corresponding transport block byapplying one of the maximum exponent matrices E(H_(S))_(i) ¹ orE(H_(S))_(i) ² in consideration of the following supportable code blocklengths.

20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 180,200, 220, 240, 260, 280, 300, 320, 360, 400, 440, 480, 520, 560, 600,640, 720, 800, 880, 960, 1040, 1120, 1200, 1280, 1440, 1600, 1760, 1920,2080, 2240, 2400, 2560, (2880, 3200, 3520, 3840, 2720, 3040, 3360,3680), 3872, 4224, 4576, 4928, 5280, 5632, 6336, 7040, 7744, 8448,(5984, 6688, 7392, 8096)

5. The terminal encodes or decodes the corresponding transport block byapplying one of the maximum exponent matrices E(H_(S))_(i) ¹ orE(H_(S))_(i) ² in consideration of the following supportable code blocklengths.

20, 30, 40, 44, 50, 60, 66, 70, 80, 88, 90, 100, 110, 120, 130, 132,140, 150, 154, 160, 176, 180, 198, 200, 220, 240, 242, 260, 264, 280,286, 296, 300, 308, 320, 330, 352, 360, 400, 440, 480, 484, 520, 528,560, 572, 600, 616, 640, 660, 704, 720, 792, 800, 880, 960, 968, 1040,1056, 1120, 1144, 1200, 1232, 1280, 1320, 1408, 1440, 1584, 1600, 1760,1920, 1936, 2080, 2112, 2240, 2288, 2400, 2464, 2560, 2640, 2816, 3168,3520, 3872, 4224, 4576, 4928, 5280, 5632, 6336, 7040, 7744, 8448, (5984,6688, 7392, 8096)

6. The terminal encodes or decodes the corresponding transport block byapplying one of the maximum exponent matrices E(H_(S))_(i) ¹ orE(H_(S))_(i) ² in consideration of the following supportable code blocklengths.

20, 30, 40, 44, 50, 60, 66, 70, 80, 88, 90, 100, 110, 120, 130, 132,140, 150, 154, 160, 176, 180, 198, 200, 220, 240, 242, 260, 264, 280,286, 296, 300, 308, 320, 330, 352, 360, 400, 440, 480, 484, 520, 528,560, 572, 600, 616, 640, 660, 704, 720, 792, 800, 880, 960, 968, 1040,1056, 1120, 1144, 1200, 1232, 1280, 1320, 1408, 1440, 1584, 1600, 1760,1920, 1936, 2080, 2112, 2240, 2288, 2400, 2464, 2560, (2720, 2816, 2880,3040, 3168, 3200, 3360, 3520, 3680, 3840), 3872, 4224, 4576, 4928, 5280,5632, 6336, 7040, 7744, 8448, (5984, 6688, 7392, 8096)

7. If the applicable code block length is one of the following values,the terminal performs encoding or decoding using the first base graph byapplying of the maximum exponent matrices E(H_(S))_(i) ¹.

110, 220, 440, 880, 1760, (3520)

8. In the case of retransmission, the terminal performs encoding anddecoding by applying one of the base graph-based E(H_(S))_(i) ¹ orE(H_(S))_(i) ² configured in initial transmission and accordinglyapplying one of the maximum exponent matrices E(H_(S))_(i) ¹ orE(H_(S))_(i) ².

If the values in the table are equal to or smaller than M, all or someof the values can be generally used while being omitted from the table.160, 640, or another value may be selected as M.

In the disclosure, values in brackets shown in a table are values thatmay be entirely or partially included in the table or may not bepartially included therein.

A process of decoding the transport block of the downlink data channelby the UE described in the disclosure can be also applied to a processof encoding a transport block of an uplink data channel.

An encoding and decoding operation of the UE described in the disclosurecan be also applied to an encoding and decoding operation of the eNB.

Embodiment 2

Embodiment 2 of the disclosure provides a method of segmenting atransport block into code blocks.

FIG. 6 illustrates the method of segmenting the transport block intocode blocks according to embodiment 2 of the disclosure. In FIG. 6 , atransport block 610 having a length N 611 is illustrated, and a CRC 620having a length L 602 may be inserted and thus a transport block 630(TC-CRC), into which the CRC is inserted, having a total length of B 601may be configured.

A length of the CRC inserted into a transmitted TB used for determiningwhether TB decoding is successful after the TB decoding is L, and L mayhave at least two available values. That is, if the transport block issegmented into two or more code blocks and transmitted, a long CRC maybe used. On the other hand, if the transport block is segmented into onecode block and transmitted, a short CRC may be used.

If the LDPC code is used for encoding in the mobile communicationsystem, the LDPC code itself has a parity check function and thussomewhat may have a function of determining whether decoding issuccessful without CRC insertion. If the LDPC code is used and it isdesired to acquire an additional decoding success determination level ina specific mobile communication system, a technology for determiningdecoding is finally successful in addition to insertion of the paritycheck function of the LDPC code may be used, and thus an error ratelevel of the determination about whether decoding is successful, desiredby the system, can be obtained. For example, if an error rate ofdetermination about whether decoding is successful, required by thesystem, is 10⁻⁶ and an error rate of determination acquired by theparity check function of the LDPC code is 10⁻³, the final systemdetermination error rate of 10⁻⁶ may be achieved by additionallyinserting the CRC having the determination error rate of 10⁻³.

In general, as the length of the CRC is longer, an error rate ofdetermination about whether decoding is successful becomes lower. If thetransport block is segmented into two or more code blocks andtransmitted, the TB itself is configured through concatenation of LDPCcodes and thus cannot use a parity check function of the LDPC code. Onthe other hand, if the transport block includes one code block, theparity check function of the LDPC code may be used. Accordingly, in aspecific system, the TB can be used after a long CRC or a short CRC isinserted into the TB according to the number of code blocks within thetransport block. In embodiments of the disclosure, it is assumed that along length L₊ or a short length L⁻ may be used as the length L of theCRC inserted into the TB according to whether the TB is segmented intotwo or more code blocks. A value available for L₊ may be 24, which isused in the LTE system, and any length shorter than 24 may be used forL⁻ and 16, which is used by the control channel of the LTE system, maybe reused. However, in embodiments of the disclosure, L⁻ is not limitedto 16.

Whether a specific TB is segmented into a plurality of code blocks isdetermined according to whether the given TB can be transmitted usingone code block, so that the determination may be performed as follows:

-   -   If N+L⁻ is equal to or smaller than the largest available CB        length, the TB is transmitted using one code block (If        (N+L⁻)<=K_(max), then one CB is used)    -   If N+L⁻ is larger than the largest available CB length, the TB        is segmented into a plurality of code blocks and transmitted (If        (N+L⁻)>K_(max), then one CB is segmented)

K_(max) indicates the largest code block size among available code blocksizes.

Hereinafter, in the disclosure, it is assumed that L₊ is used for thelength of the CRC included in the TB to indicate a segmentation methodwhen the TB-CRC is segmented into a plurality of code blocks andtransmitted. That is, whether to segment the TB by the eNB and theterminal may be determined on the basis of N+L⁻, but if it is determinedto segment the same, the segmentation is performed on the basis ofB=(N+L₊).

FIG. 6 illustrates an example in which the TB-CRC 630 having the lengthB (=N+L₊) is segmented into a total of C(=C₊+C) CBs 606, 607, 608, and609. The segmented C code blocks may include a total of C⁻ CBs from CB#1 606 to CB #M 607 (where M may be C) having a code block size K⁻ 604and a total of C₊ CBs from CB #(M+1) 608 to CB #C 609 having a codeblock size K₊ 605. In the example of FIG. 6 , one transport block may besegmented into a plurality of code blocks having various code blocksizes. The CRC 620 having a length L 602 may be additionally insertedinto each code block. The length L of the CRC inserted into the CBs 606,607, 608, and 609 may be different from L of the CRC inserted into theTB 630. Further, the CRC inserted into the CB may be different from theCRC inserted into the TB.

FIG. 7 illustrates a method of segmenting a transport block according toembodiment 2 of the disclosure. Referring to FIG. 7 , embodiment 2 ofthe disclosure may include the following steps.

Step 700: determine the number (C) of all code blocks

Step 710: determine an expected size (B′) after segmentation into thecode blocks

Step 720: determine a first code block size (K₊)

Step 730: determine a second code block size (K⁻)

Step 740: determine the number (C⁻) of code blocks having the secondcode block size (K⁻)

Step 750: determine the number (C₊) of code blocks having the first codeblock size (K₊)

Step 760: determine the number of filler bits

Step 770: insert filler bits

Hereinafter, each step will be described in detail.

In step 700, the number C of all code blocks segmented from onetransport block may be determined, which may be obtained through amethod such as [Equation 10] below.C−(B/(K _(max) −L))  [Equation 10]

In [Equation 10] above, K_(max) is the largest code block size amongavailable code block sizes. (x) operation is a ceiling operation for xand indicates a function corresponding to the smallest integer largerthan or equal to a real number x. Through [Equation 10] above, thenumber of code blocks generated after segmentation of the transportblock may be minimized. K_(max) may have a value, for example, 8448.

In step 710, an expected size B′ of all blocks after segmentation intothe code blocks may be determined on the basis of the number of codeblocks determined in step 700. This may follow, for example, [Equation11] below.B′=B+C·L  [Equation 11]

According to [Equation 11] above, the expected size B′ after thesegmentation into the code blocks may be determined by the size B,obtained by adding the transport block before the segmentation into thecode blocks and the CRC for the transport block, and the size CL of allCRCs added after the segmentation into the code blocks.

In step 720, a first code block size (K₊) may be determined. The firstcode block size may be determined to be the smallest value larger thanB′/C. This may be indicated by [Equation 12] below.K ₊=minimumK s.t. C·K≥B′  [Equation 12]

Through [Equation 12] above, the first code block size closest to thewhole length B′ after the segmentation may be selected.

In step 730, a second code block size K⁻ may be determined. The secondcode block size may be determined to be the smallest value larger thanB′/C. This may be indicated by [Equation 13] below.K ⁻=maximum K s.t. K<K ₊ and E(H _(S) ^((K)))=E(H _(S) ^((K) ⁺⁾)  [Equation 13]

In [Equation 13] above, E(H_(S) ^((K))) is defined as a maximum exponentmatrix of a parity check matrix for a code block having a code blocklength K. In determination of the second code block size through[Equation 12] above, the largest value among code block sizes smallerthan the first code block size may be selected. In determination of thesecond code block size through the condition E(H_(S) ^((K)))=E(H_(S)^((K) ⁺ ⁾) of [Equation 13] above, the sameness between maximum exponentmatrices of the parity check matrix for code blocks having the firstcode block size and the second code block size may be guaranteed. In amore detailed example, different maximum exponent matrices of paritycheck matrices may be defined according to supportable code block sizes.If a set of all supportable code block sizes is {K1, K2, . . . , KN} anda set of supportable maximum exponent matrices is {E(H_(S))₁, E(H_(S))₂,. . . , E(H_(S))_(M)}, [Equation 14] below may be satisfied.E(H ^((K) ^(n) ⁾)∈{E(H _(S))₁ ,E(H _(S))₂ , . . . ,E(H _(S))_(M)} for1≤n≤N  [Equation 14]

Accordingly, a set of code block sizes having the same maximum exponentmatrix may be defined through [Equation 15] below.

$\begin{matrix}{S_{1} = \left\{ {{{{K_{n}{for}1} \leq n \leq N}❘{E\left( H_{S}^{(K_{n})} \right)}} = {E\left( H_{S} \right)}_{1}} \right\}} & \left\lbrack {{Equation}15} \right\rbrack\end{matrix}$ S₂ = {K_(n)for1 ≤ n ≤ N❘E(H_(S)^((K_(n)))) = E(H_(S))₂} ⋮S_(M) = {K_(n)for1 ≤ n ≤ N❘E(H_(S)^((K_(n)))) = E(H_(S))_(M)}

In [Equation 15] above, S_(m) may be defined as a set of code blocksizes having exponent matrices E(H)_(m) of the parity check matrix.[Equation 13] above is described below with reference to [Equation 15]above. If it is assumed that a maximum exponent matrix for the codeblock having the first code block size determined through [Equation 12]is E(H^((K+)))=E(H)_(m), the first code block may be an elementbelonging to S_(m) in [Equation 15] above. According to [Equation 13]above, the second code block size may be determined as the largest Kvalue smaller than the first code block size among elements of S_(m) in[Equation 15] above. [Equation 16] may be derived from [Equation 13]using [Equation 15].K ⁻=maximum K s.t. K<K ₊ and K∈S ^((K) ⁺ ⁾  [Equation 16]

In [Equation 16] above, S^((K) ⁺ ⁾ may be defined as a set ofpredetermined code block sizes including the first code block size. Theset of the code block sizes may be defined as a set of code block sizeshaving the same exponent matrix through a method such as [Equation 15]above. According to [Equation 16], in determination of the second codeblock size, an operation for selecting one of the elements within theset of code block sizes, which is the same as the first code block size,may be performed.

Hereinafter, an example of a set of code block sizes having the sameexponent matrix described above will be provided. A set of allsupportable code block sizes may be as follows.

44, 66, 88, 110, 132, 154, 176, 198, 220, 242, 264, 286, 308, 330, 352,296, 440, 484, 528, 572, 616, 660, 704, 792, 880, 968, 1056, 1144, 1232,1320, 1408, 1584, 1760, 1936, 2112, 2288, 2464, 2640, 2816, 3168, 3520,3872, 4224, 4576, 4928, 5280, 5632, 6336, 7040, 7744, 8448, (5984, 6688,7392, 8096)

(5984, 6688, 7392, 8096) may be values that may be additionallyincluded. A set of supportable maximum exponent matrices may be asfollows.

-   -   {E(H_(S))₁, E(H_(S))₂, E(H_(S))₃, E(H_(S))₄, E(H_(S))₅,        E(H_(S))₆, E(H_(S))₇, E(H_(S))₈}

A set of code block sizes having exponent matrices of the same paritycheck matrix may be as follows.S ₁ ={K _(n) for 1≤n≤N|E(H ^((K) ^(n) ⁾)=E(H _(S))₁}S ₂ ={K _(n) for 1≤n≤N|E(H ^((K) ^(n) ⁾)=E(H _(S))₂}S ₃ ={K _(n) for 1≤n≤N|E(H ^((K) ^(n) ⁾)=E(H _(S))₃}S ₄ ={K _(n) for 1≤n≤N|E(H ^((K) ^(n) ⁾)=E(H _(S))₄}S ₅ ={K _(n) for 1≤n≤N|E(H ^((K) ^(n) ⁾)=E(H _(S))₅}S ₆ ={K _(n) for 1≤n≤N|E(H ^((K) ^(n) ⁾)=E(H _(S))₆}S ₇ ={K _(n) for 1≤n≤N|E(H ^((K) ^(n) ⁾)=E(H _(S))₇}S ₈ ={K _(n) for 1≤n≤N|E(H ^((K) ^(n) ⁾)=E(H _(S))₈}

A set of code block sizes that satisfy the above conditions may be asfollows.

-   -   S₁={44, 88, 176, 352, 704, 1408, 2861, 5632}    -   S₂={66, 132, 264, 528, 1056, 2112, 4224, 8448}    -   S₃={110, 220, 440, 880, 1760, 3520, 7040}    -   S₄={154, 308, 616, 1232, 2464, 4928}    -   S₅={198, 396, 792, 1584, 3168, 6336}    -   S₆={242, 484, 968, 1936, 3872, 7744}    -   S₇={286, 572, 1144, 2288, 4576}    -   S₈={330, 660, 1320, 2640, 5280}

In step 740, the number C⁻ of code blocks having the second code blocksize K⁻ may be determined. For example, the number C⁻ of code blocks mayfollow [Equation 17].

$\begin{matrix}{C_{-} = {{\left\lfloor \frac{{C \cdot K_{+}} - B^{\prime}}{\Delta_{K}} \right\rfloor{where}\Delta_{K}} = {K_{+} - K_{-}}}} & \left\lbrack {{Equation}17} \right\rbrack\end{matrix}$

In [Equation 17], *x⁺ operation is a floor operation and indicates afunction corresponding to the largest integer equal to or smaller than areal number x.

Subsequently, in step 750, the number C₊ of code blocks having the firstcode block size K₊ may be determined. For example, the number of codeblocks may follow [Equation 18] below.C ₊ =C−C ⁻  [Equation 18]

In methods such as step 740 and step 750 in which the number of codeblocks having the second code block size and the number of code blockshaving the first code block size are determined, the number of codeblocks having the first code block size may be maximized and the numberof code blocks having the second code block size may be minimizedthrough [Equation 17] and [Equation 18].

In step 760, the number of filler bits may be determined. The fillerbits are bits additionally inserted when the block size aftersegmentation into final code blocks determined through steps 700 to 750is larger than the expected block size B′ after segmentation into codeblocks determined in step 710. This may be indicated by, for example,[Equation 19] below.F=C ₊ ·K ₊ +C ⁻ ·K ⁻ −B′  [Equation 19]

In step 770, F filler bits determined in step 707 may be inserted into aspecific code block. A method of inserting the filler bits may followthe following embodiments.

Embodiment 2-1

In embodiment 2-1 of the disclosure, in insertion of filler bits into aspecific code block during segmentation of a transport block into codeblocks, all filler bits having the size of F may be inserted into onespecific code block. The specific code block may be, for example, afirst code block among code blocks generated after the segmentation intothe code blocks.

Embodiment 2-2

In embodiment 2-2 of the disclosure, in insertion of filler bits into aspecific code block during segmentation of a transport block into codeblocks, filler bits having the size of F may be uniformly distributedand inserted into all code blocks. More specifically, filler bits havinga first filler bit size may be inserted into first N code blocks amongall C code blocks, and filler bits having a second filler bit size maybe inserted into the remaining M code blocks. For example, N, M, thefirst filler bit size F₊, and the second filler bit size F⁻ may bedetermined through [Equation 20] below.N=FmodC,M=C−N,F ₊=(F/C),F ⁻ =F ₊−1  [Equation 20]

[Equation 20] above may minimize a difference between the first filerbit size and the second filler bit size to be 1. Accordingly, this hasan advantage of guaranteeing the most uniform filler bit insertion.

Embodiment 2-3

In embodiment 2-3 of the disclosure, in insertion of filler bits into aspecific code block during segmentation of a transport block into codeblocks, F filler bits may be uniformly distributed and inserted into allcode blocks having a first code block size. More specifically, fillerbits having a first code block size F₊ may be inserted into first N₊code blocks among all C₊ code blocks having the first code block size,and filler bits having a second filler bit size F⁻ may be inserted intothe remaining M₊ code blocks. For example, N₊, M₊, the first filler bitsize F₊, and the second filler bit size F⁻ may be determined through[Equation 21] below.N ₊=FmodC₊ ,M ₊ =C ₊ −N ₊ ,F ₊=(F/C ₊),F ⁻ =F ₊−1  [Equation 21]

Embodiment 2-4

In embodiment 2-4 of the disclosure, in insertion of filler bits into aspecific code block during segmentation of a transport block into codeblocks, filler bits having the size of F may be uniformly distributedand inserted into all code blocks having a second code block size. Morespecifically, filler bits having a first code block size F₊ may beinserted into first N⁻ code blocks among all C⁻ code blocks having thesecond code block size, and filler bits having a second filler bit sizeE may be inserted into the remaining M⁻ code blocks. For example, N_,M_, the first filler bit size F+, and the second filler bit size E maybe determined through [Equation 22] below.N ⁻=FmodC⁻ ,M ⁻ ,C ⁻ −N ⁻ ,F ₊=(F/C ⁻),F ⁻ =F ₊−1  [Equation 22]

Embodiment 2-5

In embodiment 2-5 of the disclosure, the second code block size may bedetermined through [Equation 23] below in step 730 considered inembodiment 2, that is, the step of determining the second code blocksize when the transport block is segmented into code blocks.K ⁻=22·a·2^(j) ⁻ ,  [Equation 23]

-   -   where j⁻=maximum j s.t j<j₊ and j₊=log₂(K₊/22·a)−1

In [Equation 23] above, supportable code block sizes K may be defined asK=22·a·2j, where a={2, 3, 5, 7, 9, 11, 13, 15} and j={0, 1, 2, 3, 4, 5,6, 7}. Accordingly, the first code block size may be defined asK₊=22·a·2^(j) ₊, and the second code block size may be defined asK⁻=22·a·2^(j) ⁻. According to [Equation 23] above, j⁻ among parametersfor determining the second code block size may be determined to be thelargest value smaller than J₊, and a among parameters for determiningthe second code blocks may be determined to be the same as a parameter afor determining the first code block size. For the condition of[Equation 13] above, that is, in determination of the second code blocksize, for example, condition 2-5-1 below should be satisfied in order toguarantee the sameness between maximum exponent matrices of the paritycheck matrix for code blocks having the first code block size and thesecond code block size.

[Condition 2-5-1]

-   -   The code block size K may be determined by a and j. For example,        K=22·a·2j.    -   A maximum exponent matrix of a parity check matrix for a code        block having the code block size K may be determined by a and j.    -   Maximum exponent matrices of a parity check matrix for a code        block having the code block size K may be the same for different        j values.    -   Maximum exponent matrices of a parity check matrix for a code        block having the code block size K may be different for        different a values.

Embodiment 2-6

In embodiment 2-6 of the disclosure, the second code block size may bedetermined through [Equation 24] below in step 730 considered inembodiment 2, that is, the step of determining the second code blocksize when the transport block is segmented into code blocks.K ⁻=maximum K s.t. K<K ₊  [Equation 24]

According to [Equation 24], the second code block size may be determinedas the largest code block size among code block sizes smaller than thefirst code block size.

Embodiment 3

Embodiment 3 of the disclosure provides a method of segmenting atransport block into code blocks.

FIG. 8 illustrates a method of segmenting a transport block into codeblocks according to embodiment 3 of the disclosure. In FIG. 8 , atransport block 810 having a length N 802 is illustrated, and a CRC 820having a length L 803 may be inserted and thus a transport block 830(TC-CRC), into which the CRC is inserted, having a total length of B 801may be configured. FIG. 8 illustrates an example in which the TB-CRC 830having the length B is segmented into a total of C CBs 806, 807, and808. The segmented code blocks may have a code block size K, and the CRC820 having the length L 805 may be inserted into each code block. Thelength L 805 of the CRC inserted into the CBs 806, 807, and 808 may bedifferent from L 803 of the CRC 820 inserted into the TB 830. Further,the CRC inserted into the CB may be different from the CRC inserted intothe TB.

FIG. 9 illustrates a method of segmenting a transport block according toembodiment 3 of the disclosure. Referring to FIG. 9 , embodiment 3 ofthe disclosure may include the following steps.

Step 900: determine the number (C) of all code blocks

Step 910: determine an expected size (B′) after segmentation into codeblocks

Step 920: determine a code block size (K)

Step 930: determine the number of filler bits

Step 940: insert filler bits

Hereinafter, each step will be described in detail.

In step 900, the number (C) of all code blocks segmented from onetransport block may be determined, which may be obtained through amethod such as [Equation 25] below.C=(B/(K _(max) −L))  [Equation 25]

Through [Equation 25] above, the number of code blocks generated aftersegmentation of the transport block may be minimized. K_(max) may have avalue, for example, 8448.

In step 910, the expected size B′ of all blocks after segmentation intocode blocks may be determined on the basis of the number of code blocksdetermined in step 900. This follows, for example, [Equation 62] below.B′=B+C·L  [Equation 26]

According to [Equation 26] above, the expected size B′ after thesegmentation into the code blocks may be determined by the size B,obtained by adding the transport block before the segmentation into thecode blocks and the CRC for the transport block, and the size CL of allCRCs added after the segmentation into the code blocks.

In step 920, the code block size K may be determined. The code blocksize may be determined to be the smallest value larger than B′/C. Thismay be indicated by [Equation 27] below.K=minimumK s.t. C·K≥B′  [Equation 27]

Through [Equation 27], a code block size which is the closest to thewhole length B′ after segmentation may be selected.

In step 930, the number of filler bits may be determined. This may bedetermined by, for example, [Equation 28] below.F=C·K−B′  [Equation 28]

In step 940, F filler bits determined in step 930 may be inserted into aspecific code block. A method of inserting filler bits may follow, forexample, embodiment 2-1 of the disclosure described above.

Embodiment 4

Embodiment 4 provides a method of obtaining and determining thetransport block size (TBS) by the eNB and the terminal.

The eNB may identify (count) how many resource elements (REs) are usedfor data transmission while allocating frequency-time resources forscheduling to the terminal. For example, if the eNB allocates 10 PRBsfrom PRB 1 to PRB 10 and allocates 7 OFDM symbols to data transmission,a total of 10×12×7, that is, 840 REs are included in the allocatedfrequency-time resources. Among the 840 REs, REs other than REs used fordemodulation reference signals (DMRSs), REs used for channel stateinformation-reference signal (CSI-RSs), and REs used for controlchannels that may exist may be used for mapping of data signals.Accordingly, the eNB and the terminal may know which REs are used fordata transmission on the basis of allocation of the frequency-timeresources. The frequency-time resources may be transferred to theterminal through physical layer or higher layer signaling.

Meanwhile, the eNB may inform the terminal of modulation and channelcoding information for scheduling. For example, information on whichmodulation scheme such as QPSK, 16-QAM, 64-QAM, 256-QAM, and 1024-QAM isused for data transmission and information on a coding rate may beincluded. This may be called a modulation and coding scheme (MCS) andvalues thereof may be defined by a predetermined table. The eNB mayinsert only an index into DCI and transmit the DCI to the terminal.Information on a modulation order (interchangeably used with an MCSscheme) in the modulation information can also be transmitted.Modulation orders of QPSK, 16-QAM, 64-QAM, 256-QAM, and 1024-QAM are 2,4, 6, 8, and 10, respectively.

The eNB obtains a final TBS through the following steps.

Step 1: obtain a temporary TBS per layer

Step 2: select a final TBS per layer

Step 3: obtain a final TBS

In step 1, a predetermined TBS per layer may be obtained through thefollowing equation.

-   -   Temporary TBS per layer=MCS order×coding rate×number of        allocated REs available for data transmission

Or

-   -   Temporary TBS per layer=value presented in MCS table×number of        allocated REs available for data transmission

The temporary TBS per layer may be obtained as described above. Thevalue presented in the MCS table may be a value reflecting the codingrate and the MCS order.

The largest value smaller than the obtained temporary TBS per layeramong values belonging to a TBS candidate set may be selected as thefinal TBS in step 2. For example, the TBS candidate set may includevalues in the following table. If the temporary TBS per layer obtainedin step 1 is 2000, the largest value smaller than 2000 may be selectedas the final TBS per layer. This is to secure an actual coding rateequal to or smaller than a coding rate aimed by the eNB.

16, 24, 32, 40, 56, 72, 88, 104, 120, 136, 144, 152, 176, 208, 224, 256,280, 288, 296, 328, 336, 344, 376, 392, 408, 424, 440, 456, 472, 488,504, 520, 536, 552, 568, 584, 600, 616, 632, 648, 680, 696, 712, 744,776, 808, 840, 872, 904, 936, 968, 1000, 1032, 1064, 1096, 1128, 1160,1192, 1224, 1256, 1288, 1320, 1352, 1384, 1416, 1480, 1544, 1608, 1672,1736, 1800, 1864, 1928, 1992, 2024, 2088, 2152, 2216, 2280, 2344, 2408,2472, 2536, 2600, 2664, 2728, 2792, 2856, 2984, 3112, 3240, 3368, 3496,3624, 3752, 3880, 4008, 4136, 4264, 4392, 4584, 4776, 4968, 5160, 5352,5544, 5736, 5992, 6200, 6456, 6712, 6968, 7224, 7480, 7736, 7992, 8248,8504, 8760, 9144, 9528, 9912, 10296, 10680, 11064, 11448, 11832, 12216,12576, 12960, 13536, 14112, 14688, 15264, 15840, 16416, 16992, 17568,18336, 19080, 19848, 20616, 21384, 22152, 22920, 23688, 24496, 25456,26416, 27376, 28336, 29296, 30576, 31704, 32856, 34008, 35160, 36696,37888, 39232, 40576, 42368, 43816, 45352, 46888, 48936, 51024, 52752,55056, 57336, 59256, 61664, 63776, 66592, 68808, 71112, 73712, 75376

In another example, among values belonging to the TBS candidate set, thesmallest value larger than the obtained temporary TBS per layer may beselected as the final TBS in step 2.

In another example, step 2 may be omitted.

In another example, step 2 may be a step for making the temporary TBSper layer obtained in step 1 be a multiple of a specific integer. Forexample, in order to make the temporary TBS per layer be a multiple ofN, N×ceil (temporary TBS per layer/N) or N×floor (temporary TBS perlayer/N) may be determined as the final TBS. ceil(X) and floor(X) may bea minimum integer larger than X and a maximum integer larger than X,respectively. N may be fixed to an integer such as 8. N may bedetermined in consideration of the case in which the number of pieces ofdata transmitted in a higher layer such as MAC or RRC is a multiple ofN.

In step 3, the final TBS may be obtained by multiplying the final TBSper layer, selected in step 2, and the number of layers.

In the TBS candidate set, elements and a maximum value may varydepending on a system frequency band, subcarrier spacing, and the numberof OFDM symbols per slot. Further, the TBS candidate set may beprearranged between the eNB and the terminal or may be configuredthrough higher layer signaling for data transmission.

The method of obtaining the TBS in step 3 may be replaced with themethod of obtaining the TBS in step 2.

Step A: obtain a temporary TBS

Step B: select a final TBS

Step A may be obtained through the following equation.

-   -   Temporary TBS per layer=MCS order×coding rate×number of        allocated REs available for data transmission×number of layers        used for transmission

Or

-   -   Temporary TBS per layer=value presented in MCS table×number of        allocated REs available for data transmission×number of layers        used for transmission

That is, the temporary TBS may be obtained by further considering thenumber of layers from step 1.

Step B is a process for obtaining the final TBS from the TBSs obtainedin step A in consideration of a TBS candidate set and may be similar tostep 2 described above.

FIGS. 10 and 11 are flowcharts illustrating processes by which the eNBand the terminal obtain a TBS. Referring to FIG. 10 , the eNB determinesscheduling information including an MCS order, a coding rate,frequency-time resource allocation, and the number of layers in step1000. Thereafter, the eNB obtains a temporary TBS per layer through thefollowing equation based on the information in step 1010.

-   -   Temporary TBS per layer=MCS order×coding rate×number of        allocated REs available for data transmission

Or

-   -   Temporary TBS per layer=value presented in MCS table×number of        allocated REs available for data transmission

Thereafter, the eNB selects a final TBS per layer from a TBS candidateset prearranged between the eNB and the terminal in step 1020, andidentifies a final TBS by multiplying the final TBS per layer and thenumber of layers in step 1030.

Referring to FIG. 11 , the terminal identifies scheduling informationincluding an MCS order, a coding rate, frequency-time resourceallocation, and the number of layers through higher layer signaling ofDCI in step 1100. The eNB and the terminal obtain a temporary TBS perlayer through the following equation based on the information in step1110.

-   -   Temporary TBS per layer=MCS order×coding rate×number of        allocated REs available for data transmission

Or

-   -   Temporary TBS per layer=value presented in MCS table×number of        allocated REs available for data transmission

Thereafter, the terminal selects a final TBS per layer from a TBScandidate set prearranged between the eNB and the terminal in step 1120.Subsequently, the terminal identifies a final TBS by multiplying thefinal TBS per layer and the number of layers in step 1130. A method ofobtaining the final TBS from the final TBS per layer can be determinedon the basis of a specific rule as well as the simple multiplicationmethod.

FIG. 12 is a block diagram illustrating the structure of the terminalaccording to embodiments of the disclosure.

Referring to FIG. 12 , the terminal according to the embodiment mayinclude a receiver 1200, a transmitter 1201, and a processor 1202. Thereceiver 1200 and the transmitter 1204 may be collectively called atransceiver in an embodiment. The transceiver may transmit and receive asignal to and from the eNB. The signal may include downlink controlinformation and data. To this end, the transceiver includes an RFtransmitter that up-converts and amplifies a frequency of a transmittedsignal and an RF receiver that low-noise amplifies a received signal anddown-converts the frequency. The transceiver may receive a signalthrough a radio channel, output the signal to the processor 1202, andtransmit the signal output from the processor 1202 through a radiochannel. The processor 1202 may control a series of processes such thatthe terminal may operate according to the aforementioned embodiment.

FIG. 13 is a block diagram illustrating the structure of the eNBaccording to embodiments of the disclosure.

Referring to FIG. 13 , the eNB according to the disclosure may includeat least one of a receiver 1301, a transmitter 1305, and a processor1303. The receiver 1301 and the transmitter 1305 may be collectivelycalled a transceiver in an embodiment of the disclosure. The transceivermay transmit and receive a signal to and from the terminal. The signalmay include downlink control information and data. To this end, thetransceiver includes an RF transmitter that up-converts and amplifies afrequency of a transmitted signal and an RF receiver that low-noiseamplifies a received signal and down-converts the frequency. Thetransceiver may receive a signal through a radio channel, output thesignal to the processor 1303, and transmit the signal output from theprocessor 1303 through a radio channel. The processor 1303 may control aseries of processes such that the eNB may operate according to theaforementioned embodiment of the disclosure.

Meanwhile, the embodiments of the disclosure disclosed in thisspecification and the drawings have been presented to easily explaintechnical contents of the disclosure and help comprehension of thedisclosure, and do not limit the scope of the disclosure. That is, it isobvious to those skilled in the art to which the disclosure belongs thatdifferent modifications can be achieved based on the technical spirit ofthe disclosure. Further, if necessary, the above respective embodimentsmay be employed in combination. For example, some of embodiment 1,embodiment 2, and embodiment 3 of the disclosure may be combined, andthe eNB and the terminal may operate therethrough. Although theembodiments are presented on the basis of the NR system, othermedication examples based on technical idea of the embodiments can beapplied to other systems such as an FDD or TDD LTE system.

Although exemplary embodiments of the disclosure have been shown anddescribed in this specification and the drawings, they are used ingeneral sense in order to easily explain technical contents of thedisclosure, and to help comprehension of the disclosure, and are notintended to limit the scope of the disclosure. It is obvious to thoseskilled in the art to which the disclosure pertains that other modifiedembodiments on the basis of the spirits of the disclosure besides theembodiments disclosed herein can be carried out.

The invention claimed is:
 1. A method performed by a user equipment (UE)in a communication system, the method comprising: receiving, from a basestation, downlink control information including resource assignmentinformation of a physical downlink shared channel (PDSCH); identifying anumber of resource elements (REs) for the PDSCH based on a number ofassigned symbols and a number of assigned physical resource blocks(PRBs), wherein a number of REs for a demodulation reference signal(DMRS) is excluded from the number of REs for the PDSCH; identifying atemporary transport block size (TBS) based on the number of REs for thePDSCH, a modulation order, a coding rate, and a number of layers;identifying a TBS based on${N \star \left\lfloor \frac{{Temporary}TBS}{N} \right\rfloor},$  whereN is an integer; and receiving, from the base station, the PDSCH basedon the TBS.
 2. The method of claim 1, wherein the number of REs for thePDSCH is identified by further excluding at least one of a number of REsassociated with a channel state information reference signal (CSI-RS) ora number of REs associated with a control channel.
 3. The method ofclaim 1, wherein a value of N is a multiple of
 8. 4. The method of claim1, wherein a value of N is
 8. 5. The method of claim 1, wherein the TBSis identified based on the temporary TBS among TBS candidates includedin a predefined TBS candidate set.
 6. A method performed by a basestation in a communication system, the method comprising: identifying atransport block size (TBS) for a physical downlink shared channel(PDSCH); transmitting, to a user equipment (UE), downlink controlinformation including a number of assigned symbols and a number ofassigned physical resource blocks (PRBs) for the PDSCH; andtransmitting, to the UE, the PDSCH based on the identified TBS, whereinthe identified TBS is associated with a temporary TBS based on${N \star \left\lfloor \frac{{Temporary}TBS}{N} \right\rfloor},$  whereN is an integer, wherein the temporary TBS is associated with a numberof resource elements (REs) for the PDSCH, modulation order, coding rateand a number of layers, and wherein the number of REs for the PDSCH isassociated with the number of assigned symbols and the number ofassigned PRBs, wherein a number of REs for a demodulation referencesignal (DMRS) is excluded for the number of REs for the PDSCH.
 7. Themethod of claim 6, wherein the number of REs for the PDSCH is identifiedby further excluding at least one of a number of REs associated with achannel state information reference signal (CSI-RS) or a number of REsassociated with a control channel.
 8. The method of claim 6, wherein avalue of N is a multiple of
 8. 9. The method of claim 6, wherein a valueof N is
 8. 10. The method of claim 6, wherein the TBS is identifiedbased on the temporary TBS among TBS candidates included in a predefinedTBS candidate set.
 11. A user equipment (UE) in a communication system,the UE comprising: a transceiver; and a controller configured to:receive, from a base station, downlink control information includingresource assignment information of a physical downlink shared channel(PDSCH), identify a number of resource elements (REs) for the PDSCHbased on a number of assigned symbols and a number of assigned physicalresource blocks (PRBs), wherein a number of REs for a demodulationreference signal (DMRS) is excluded for the number of REs for the PDSCH,identify a temporary transport block size (TBS) based on the number ofREs for the PDSCH, a modulation order, a coding rate, and a number oflayers, identify a TBS based on${N \star \left\lfloor \frac{{Temporary}TBS}{N} \right\rfloor},$  whereN is an integer, and receive, from the base station, the PDSCH based onthe TBS.
 12. The UE of claim 11, wherein the number of REs for the PDSCHis identified by further excluding at least one of a number of REsassociated with a channel state information reference signal (CSI-RS) ora number of REs associated with a control channel.
 13. The UE of claim11, wherein a value of N is a multiple of
 8. 14. The UE of claim 11,wherein a value of N is a
 8. 15. The UE of claim 11, wherein the TBS isidentified based on the temporary TBS among TBS candidates included in apredefined TBS candidate set.
 16. A base station in a communicationsystem, the base station comprising: a transceiver; and a controllerconfigured to: identify a transport block size (TBS) for a physicaldownlink shared channel (PDSCH), transmit, to a user equipment (UE),downlink control information including a number of assigned symbols anda number of assigned physical resource blocks (PRBs) for the PDSCH, andtransmit, to the UE, the PDSCH based on the identified TBS, wherein theidentified TBS is associated with a temporary TBS based on${N \star \left\lfloor \frac{{Temporary}TBS}{N} \right\rfloor},$  whereN is an integer, wherein the temporary TBS is associated with a numberof resource elements (REs) for the PDSCH, modulation order, coding rateand a number of layers, and wherein the number of REs for the PDSCH isassociated with the number of assigned symbols and the number ofassigned PRBs, wherein a number of REs for a demodulation referencesignal (DMRS) is excluded for the number of REs for the PDSCH.
 17. Thebase station of claim 16, wherein the number of REs for the PDSCH isidentified by further excluding at least one of a number of REsassociated with a channel state information reference signal (CSI-RS) ora number of REs associated with a control channel.
 18. The base stationof claim 16, wherein a value of N is a multiple of
 8. 19. The basestation of claim 16, wherein a value of N is
 8. 20. The base station ofclaim 16, wherein the TBS is identified based on the temporary TBS amongTBS candidates included in a predefined TBS candidate set.